If they have a "MyCharlie" account, it's registered to them, that's the whole point. It doesn't change the appearance of the card.

Regardless, when someone loses something on the T, they usually call the MBTA as soon as they notice it's missing, they don't go to r/boston to see if someone picked up a wallet full of cash and brought it home with them. If the owner calls the MBTA now to say they lost their wallet, the MBTA isn't going to have it.