I expect if the police get possession of the phone then they will have the tools to see all your contacts and locations. They can then go and harass those people.
Even if they have no such ability, possessing the phone means they will tell the suspect that they can and are just awaiting their nerd to have a look.
Also how much of this new addition to the OS is running when the app is not installed? I suspect that Apple and Google made the important part of the app and all NHSX did was hook the API into something that writes files.
Biting the hand that feeds IT
