How long would it take for nobody to take the first temptation?

So the first temptation this season was anonymously taking $25,000. Doing it on one of the first days, when nobody knew each other well at all, made it a 100% possibility of someone taking the cash.

My question is: How few players would have to be in the game for it to be a realistic chance that nobody would take the cash? How long would these people need to be with each other to not want to potentially screw the other's over ("Every temptation has a consequence...") for $25,000?