Bluetooth tracker in a postcard and mailed to a warship exposed its location
tomshardware.com
tomshardware.com
The only reason these are useful is because of the vast amount of phones that will report the location of the bluetooth tracker. A $10 chinese version wouldn’t work so well.
https://hackaday.com/2022/02/22/no-privacy-cloning-the-airta...
https://hackaday.com/2025/03/03/hijacking-airtag-infrastruct...
Not sure how different it works from Apple/Samsung trackers. But my Motorola Android phone can set it up, and phones out and about are reporting where it is.
You can get $7 MFi licensed versions these days from the dollar store https://kalleboo.com/linked/daiso-airtag.jpg
https://www.apple.com/newsroom/2021/04/apples-find-my-networ...