Participants would know quite accurately how many villain points they should be getting. Yet the end result of who got in wouldn't directly reflect that. Especially those who thought they would make it but didn't would want to find out. Considering Izuku had a zero villain score and the only thing he did was a single act of rescue, it doesn't take much to deduce something.

It's true absolutely nobody would tell if they were asked not to. But, you know, there's always that anonymous guy in the internets who reveals juicy facts just to make himself look more important.