Moral in the case of the waitress. Keep it to yourself unless someone actually come back in the restaurant asking.
“I was walking down fifth avenue today and I found a wallet, and I was gonna keep it, rather than return it, but I thought: well, if I lost a hundred and fifty dollars, how would I feel? And I realized I would want to be taught a lesson.” ~Emo Philips
I once had a 16' flatbed trailer abandoned on my property. I called the police, presuming it had been stolen, emptied, and dumped. After taking the report, the officer asked if I wanted it hauled away. I inquired what would happen if it were, and what would happen if I kept it. He stated the city would sell it if not claimed, or I could keep it, but would have to give it up if claimed. I told him he had my number in the report, if they found the owner, and to told him goodbye.