Is it normal for internet people to can keep something secret?

On a forum Im on some of them have a chat on another site where the cool members hang out but everyone else cant get in. Well they finally let me in to their club. A few people were on cam and one was a girl. Its fun seeing people on cam when normally you only talk to them on forum. Well anyways she flashed her tits! It was epic but they told me shes done it before. Fridge logic! Shes done it so why didnt everyone on the forum know about it. Shes popular so everyone would know something like that. Are they trolling me? Because it would be so crazy if they could hide something like that only they know or girls who flash always get away with it she does have alot of fun XD.