I did something similar a few months ago.
I was at a casino in Oklahoma (I know enough and I don't play) practicing my backcount.
They have this promotion where you can place a side bet of fifty cents and if one of several things happen you win a progressive pot. One of the things is a suited 6-7-8.
Well this ploppy had his main bet of $150 down as well as the side bet. The suited 6-7-8 came up and this ploppy won the progressive pot of around $4500. The dealer announced it, everbody clapped and the player was paid off.
The dealer proceeded to draw to a 17. The dealer then paid everyone off who had higher then 17, everyone but the player who hit the suited 6-7-8 that is. The dealer then was in the process of picking up the cards. I then said "hey dealer you didn't pay this guy off", point to the suited 6-7-8's.
The dealer then went blank. I said "he won the jackpot and he won his main bet also so you owe him another $150, he had a suited 6-7-8 so that's 21 and you had 17, you owe him another $150". The dealer then called the pit boss who didn't know anything. At that point the player said "it's allright, I won the jackpot", seemingly not wanting to cause a stir. I said nothing further, if the player doesn't want help I won't force it upon him.
But the pit was already involved at that point. The pit said "did you pay him for his win?" and the dealer said no. "Pay him" the pit said. The dealer then gave me a "go-to-hell" look for making him look stupid and the player gave me $50.
I don't play at these casino's in Oklahoma because of the fifty cent ante so I guess I didn't lose out on anything. And anyway the pit wasn't mad or anything.
I guess people who have a problem with helping someone who is getting cheated just don't have a clue. Helping this player cost me nothing and I can look in the mirror in the morning with a straight face.