In the Barney Suit episode (i believe it was the 100th episode), Marshal slaps Barney and there is no mention of this being one of the 5 slaps. Did anyone else notice this?

Well, I just saw it again, and it's not really a slap. It's more like a little pad on his face, to get him to stop sniffing/hugging Marshall's suit. A real slap should be as hard as he can.