This isn't an unreasonable idea, but there's a population of 7+ million Americans, especially aging ones, who might be adverse to ID tattoos for reasons that go a bit beyond privacy issues. A non-(easily)-removable bracelet might be more acceptable.
Yeah, if you could make a suitable bracelet it would be even better because it could be fitted with something akin to an AirTag.
I think an AirTag in a shoe would be best. Also a good idea for little kids.
I've hot glued AirTag to their shoe. Dementia is not a simple problem. This solution works in some of the stages of dementia. At stage 5 they don't even wear shoes when they wander off.
Or we could just cut straight to the chase and put a microchip in them.
A microchip is too small, it can't have the range needed.
This is exactly what exists, the article covers this towards the end.