I found a Visa gift card on the ground... legal trouble for spending it?

I found a Visa gift card worth $100 on the ground next to my car... it was in a corwded parking lot in a shopping plaza. I have no way of finding who this card belongs to. Can i get in trouble for spending the money on it? (i mean legally, not morally). I know its not mine, but its an unsigned gift card with no name on it... not a credit card...