Rol will hopefully come back. I think his pride has been beaten a little bit because he expects himself to be playing at a top level right away. I'm sure he thought of himself as playing his best.
However, there just isn't anything more helpful than actually time spent playing and understanding the rules and the mechanics. A veteran would look at a second cop and say liar. Why? Because they are simply smarter. No that's not it. It's because those players themselves were fooled once.
In fact, most of the players playing had been around at the time of Stefl's first fake cop claim. He tends to do it a lot. Anyway, he got away with...er..murder, by fakeclaiming cop once. Fooled everyone. That's just how you learn.