[dicknuckle]

On my Android phone, the homescreen can have a short message, I changed it to "If found, call {wife's phone number}"

[theendisney2]

I know, great in theory but i havent seen one where it was configured. You can also configure a phone number to call. No one apparently does that.

The solution needs to not require any configuration.

You can call your own phone of course but then i have to keep it charged. If it dies the sim locks.

[mgarciaisaia]

Whenever I go to big concerts or gatherings, I set my lock screen to a screenshot of a WhatsApp story (that I never publish) saying something like that.