After seeing several cases in my country of men with a restraining order about women that have ended badly, I have thought that the victim could be warned if his attacker is nearby. Even if the aggressor is not aware of the proximity, the victim would be aware of it and could be alert or leave.
But, how do you propose to permanently identifying an “attacker” (your words) so that potential victims could become aware of a possible threat?
Secondary to that how do you propose to get around the 4th Amendment issues such as tracking people? This could be a VERY serious issue.
I was thinking the same thing, forcing attackers to carry trackers would never work . If i was going to attack someone i wouldn’t carry a tracker lol. but I can see a use case involving using as an emergency alert. for example set up devices to call police, security etc on a double click. similar to “life alert” devices. Or closer to the original use case possibly force sex offenders to either carry them similar to an ankle monitor or place them on their property so people can be alerted to their presence or place them in areas they are not allowed (playgrounds, schools, etc) and if a witness is created between the sex offender and the off limits area it would alert authorities.