My point was that if OP's son is still terrified of getting lost, it might help him to have concrete plans in advance that come from an authority figure, includ

My point was that if OP's son is still terrified of getting lost, it might help him to have concrete plans in advance that come from an authority figure, including a plan that doesn't rely on having a specific device, charge, and signal each time. The specifics of whom to approach are up to the parent and child - I'm just giving one example. Also, I think "victim blaming" isn't an apt term in this case. Getting lost is almost never caused by someone being victimized, it's caused by lack of attention and then lack of a way to resolve the situation on your own.