I have an interesting question for all those hung up on a sense of "honor" regarding this issue.
Let's suppose you're on the hill and the winner gets $1000 cash. Or it's an APA match and the winner goes to Vegas.
You win the game but moments after the victory, a good friend/teammate approaches you and informs you that you committed an unintentional foul while shooting the money ball that you were unaware of and would surely have given your opponent the victory had he called you on it. You look at the rule book and sure enough, you commited a foul.
Do you concede the victory and award the $1000 to your opponent?
Do you concede the APA match to your opponents despite the pleas of your teamates.
An interesting scenario.....
First of all, I'd let results stand...whether I was the winner or the loser.
Secondly, why would the friend/teammate say anything after the fact...
..speak up at the time or hold your peace.
Thirdly, I would do something in compensation for the one who was wronged.
I was in a strange situation once....4 of us were side-betting on a game.
The man lost and paid off to us and the player.
The balls were racked for the next game but this man went to the toilet.
When he came back, he paid us off again and then started playing.
I saw that the side bettors and the player were delighted to get paid
twice.....so I held my peace.
...but over the next month, I did that man a lot of action favors, which
resulted in him winning a lot more money than he lost that day.
We're all human, life isn't perfect....
...sometimes you just do what you can.