I briefly heard a news story about a homeless man who accidentally left $187,000 in a cab. The Cabbie return the $187,000. The homeless man gave him $100 reward. Fair?

Not Fair. He should have given $500-1000. Most people said they would have kept it all or took out $5000. 🤗

I think that any reward is fair. The money did not belong to the cabbie, and he did what he was suppose to do. He turned it over to the cops. The person who lost the money was homeless and had just inherited the money.  Hopefully this will be what he needs to get his life back on track.

I forget---remind me what the going rate is for doing the morally right thing?

Late edit:  

 I seriously doubt that a homeless man who has just inherited $187,000 has yet developed any feel for what that amount of money can do for him.

I suspect that to him, even with $187,000 in his backpack (or whatever it was in) that $100 he gave as a reward in his mind still represented a "small fortune."

As the pope recently remarked---"Who am I to judge."

The cabbie did the right thing. He shouldn't expect any reward but it was nice that the guy gave him $100.

Absolutely .. He could have not bothered to pay him anything at all. This "homeless" guy who carries this kind of cash around and living on the streets obviously has some deep psychological issues .. Returning the money to someone (whether or not they have a deminished capacity ) is done because it is the right thing to do ., period. The reward  of money is irrelevant .. The true reward is a clear conscience

I suppose that Yogi Berra defined the parameters for just this situation. He was once asked what he would do if he found $1 million in the street. His reply: "I'd track down the owner and if it was a poor person I'd give it back."

Rewards for doing the decent thing? See Tom's answer. He nailed it.