Tile already has this feature. You need to pass verification to use it, but it stays undetectable. However, if you got caught stalking somebody you have to pay $1M fine.
It’s arguably pointless.
> despite the absence of the device on Tile’s app, it can still be tracked and located through other means available on the device.
> Tile Tracker with Anti-Theft mode has a static Mac-Address, which may make it even more trackable
https://techryptic.github.io/2023/03/11/Tile-Anti-Theft-Mode...
Also, tile has a really useless network. I marked mine lost and carried it through a busy city for a month until it got picked up :P
It's probably because the only people using the app are those that bought one and they're not very common here in Europe. With Apple's, Samsung's and Google's network most phones report them. Not just those of the people who own a tag.