The intent in that scenario is to wipe your phone (destroy evidence) when a bag is searched by federal agents.

I think there's a version of this where you can reasonably say you forgot you'd set this up. Like if they disassemble your whole bag, lay the BLE beacon out, and wipe the phone... You can claim it's a theft deterrent for thieves who might steal your bag and rummage thru it?

I think this sums it up for me:

- wipe-on-lost-signal = easier to claim as legitimate anti-theft mechanism. Harder to claim you forgot about it (because you'd have the actively live a life where they don't lose signal)

- wipe-on-found-signal = easier to claim as accident. ("I forgot that little faraday keychain was in my bag, and haven't touched it in years since I was on company project X"). Harder to claim it's a general anti-theft mechanism, as it requires a threat model of someone laying all your stuff out together on a table.

EDIT: Maybe it's in a little pouch attached to the phone itself, and they think it's a find-my-object tracker to inspect, but it's actually a beacon that wipes on detection. But yes, this is getting a little ridiculous in terms of plausible deniability :)