Sirence

If they have an ankle monitor, there is probably some sort of proof. Otherwise the app would probably be the least of your worries. Your theory about tracking the stalker is pretty useless because most people want to avoid their stalker at all cost and not track them down.

Also if the police only reached out to you when your stalker is 200m away how would they arrive in time to help you.

Then they should have thought of that before they started harassing someone.