Prohibition Orders Can't Stop Stalkers — The Case for Mandatory GPS Monitoring

On March 26, 2026, a 21-year-old female employee at the Pokémon Center Mega Tokyo in Ikebukuro was stabbed to death by her 22-year-old former partner. The perpetrator had a prior arrest under the Stalker Regulation Act and had signed a prohibition order. He had reportedly refused to attend counseling.

This case is not an isolated aberration. According to the National Police Agency, stalking consultations in 2024 reached 19,567[1]. Prohibition orders issued reached 2,415 (up 23.0% year-on-year)[1] — the first time the figure has exceeded 2,000 — and arrests hit 1,341 arrests, up 260 or 24.1% on the year[2]. At first glance these numbers suggest the system is gaining traction. But ask what happens after a prohibition order is issued, and a different picture emerges.

Police outreach to connect perpetrators with counselling is growing, but the orders of magnitude do not meet. From March 2024 the National Police Agency stepped up both contact with perpetrators under prohibition orders and referral to counselling and treatment. Prohibition orders came to 3,037 in 2025, a post-enactment high[3], yet contacts with perpetrators numbered 1,698 and 233 people were connected to counselling or treatment[3]. The year before, contacts numbered 1,039[2] and 184 people reached treatment.

Both are rising — contacts by 63.4%, people reached by treatment by 26.6%. Even so, in a year with 3,037 prohibition orders, treatment reached 233 people. The agency publishes no rate dividing one by the other (one counts cases, the other counts people, so they do not divide cleanly). The distance between the number of orders and the number treated is legible all the same. Most perpetrators, once an order is issued, never reach the entrance to rehabilitation. The Ikebukuro attacker was among them.

The Stalker Regulation Act: a chronology of reform

The Stalker Regulation Act was enacted in 2000 and has been revised multiple times since. The 2013 amendment added continuous messaging (email, messaging apps) to the list of regulated acts; 2016 expanded the category of loitering behaviors. The 2021 amendment criminalized the covert acquisition of GPS location data, and the 2025 amendment explicitly prohibited small tracking devices such as AirTag and authorized police to issue administrative warnings on their own initiative.

Each reform has produced higher consultation and arrest figures — evidence that legislation has real power to make harms visible. But visibility is not eradication. Notably, the AirTag-facilitated stalking that the 2025 reform targeted had already surged: cases of attaching a GPS device to another person's belongings without consent rose from 109 in 2021 to 267, 340, 354 and 393 through 2025, while unauthorised collection of location data went from 43 to 118[4]. GPS technology is spreading rapidly as a tool of victimization, the very threat now being proposed as a protective mechanism.

GPS precursors: South Korea and the United States

South Korea introduced GPS electronic anklets for sex offenders in 2008 and expanded the program to stalking offenders in 2014. JBpress reporting documents that after the program's introduction, sex-crime recidivism fell from 14.1% to 1.7% — a reduction of approximately 88%[5]. Offenders wear the ankle device throughout daily life; if they approach a designated exclusion zone (the victim's home, workplace, or school), an alert is simultaneously sent to a monitoring center, the offender, and the victim.

How the US applies and evaluates it

In the United States, the National Institute of Justice (NIJ) has analyzed the effectiveness of GPS monitoring, reporting a trend toward lower rates of protective-order violation among GPS-monitored groups.

Analysis in Keio University's law review (see the Korean stalking law study) emphasizes that the critical feature of the Korean system is judicial authorization: courts review and approve each device order, so the decision is not left to administrative discretion. This limits human-rights exposure and provides a procedural safeguard.

The post-order gap and the "get-away-with-it" structure

The core problem of Japan's current system concentrates in one question: what happens after a prohibition order is issued? The offender signs the order as an administrative act; beyond that, there is virtually no mechanism to monitor compliance. A violation — returning to an exclusion zone, resuming contact — typically comes to light only when the victim files another report or when new harm has already occurred.

The Ikebukuro case is a textbook instance of this gap. The perpetrator refused counseling after the prohibition order, and that refusal continued without triggering active intervention — because current law lacks both the mandate and the tools to compel engagement. As long as counseling participation is voluntary, refusing it is a legally permissible act within the system.

The AirTag paradox

The 2025 reform criminalized AirTag-based tracking. The irony is striking: at the very moment policy debate is intensifying around making offenders wear GPS devices, offenders are rapidly adopting GPS as a weapon against victims — concealing trackers in victims' belongings or vehicles to harvest location data. The recorded counts likely undercount the true prevalence.

What this paradox reveals is the neutrality of GPS technology. The same technology can protect or threaten. In policy design, the key question is not "who wears the GPS?" but "who owns the information?"

Constitutional constraints and the bail GPS precedent

The primary legal objection to mandatory GPS monitoring concerns constitutional limits. Article 13 of the Constitution (right to privacy, pursuit of happiness) and Article 18 (freedom from physical servitude) are the main flash points.

A critical domestic precedent arrived in 2023, when Code of Criminal Procedure amendments legalized GPS monitoring of defendants released on bail. This embedded court-authorized electronic monitoring into Japanese law for the first time. Professor Shuichiro Hoshi of Tokyo Metropolitan University notes that while "how narrowly to define the target group" remains a challenge, the bail-GPS system may serve as a legal precedent. A KAKENHI-funded study at Kokugakuin University identifies the need for "clear purpose, limited scope, and strict judicial procedures" as conditions for any GPS mandate, while maintaining a cautious stance toward blanket application to sex offenders.

The "dual-notification" design reframe

A frequently overlooked dimension of the GPS debate concerns framing. Conventional discourse centers on "monitoring the offender" — a frame that invites human-rights objections. What the Korean model actually delivers, at its core, is immediate notification to the victim. The instant an offender crosses into an exclusion zone, the victim receives an alert. Designed this way, the system is more accurately described as a "victim protection notification system" than an "offender surveillance system."

This reframe is consequential for building consensus. Shifting the question from "should the state track individuals continuously?" to "should victims have the right to advance warning of an offender's approach?" changes the moral terrain of the debate.

Mandatory rehabilitation as the other half of the equation

GPS monitoring alone is insufficient. South Korea's approximately 88% reduction in recidivism reflects the combination of GPS and compulsory rehabilitation programs. That a year with 3,037 prohibition orders reached only 233 people with treatment demonstrates the ceiling of voluntary systems.

One design option treats counseling refusal as equivalent to a prohibition-order violation — grounds for arrest. Another conditions continued GPS-free status on completion of a certified rehabilitation program. Either way, the program content itself requires upgrading. Cognitive-behavioral therapy offered on a drop-in, voluntary basis does not reach an offender who has signed a prohibition order and then walked away. Risk-stratified intervention — mapping offender type (former partner, workplace superior, stranger) against evidence-based recidivism predictors — is a necessary starting point for any redesign.

A staged model of intervention, combining an analysis of who the perpetrator is — a former partner, a workplace superior, a stranger — with an assessment of reoffending risk, would be the starting point for designing the scheme.

For further reading, 「ストーカー」は何を考えているか(What Is a Stalker Thinking?)（外部サイト、新しいタブで開きます） by Akiko Kobayakawa (Shinchosha, Shinsho) provides a rare inside view of stalker psychology drawn from more than 500 counseling cases handled through an NPO specializing in stalker rehabilitation. The book is particularly valuable for understanding how risk assessment and intervention design differ across offender types — former partners, workplace acquaintances, and strangers.

References

Overview of Stalking Cases in FY2024 (Public Relations Materials) — National Police Agency (2024)

How South Korean Society Has Changed Since GPS Anklets Were Introduced for Stalkers — JBpress (2024)

Human Rights and Electronic Surveillance (KAKENHI Research Report) — KAKENHI Project 17K03435 (2018)

GPS Monitoring Technologies and Domestic Violence: An Assessment of the Feasibility of a Randomized Experiment — National Institute of Justice (2012)

Legislative Process and Legal Structure of South Korea's Two Stalking-Response Laws — Keio University Law Review (2025)

Overview of Stalking Cases in FY2025 — National Police Agency (2025)