Yeah, you're right. Check raising in a game will keep the other players on their toes, because they can't be sure if a check from you is a sign of weakness or strength. This added doubt in their mind might keep them from betting marginal hands in the future after you check to them. Conversely, a player who never check raises will be admitting weakness everytime they check in a game. I think Sklansky said this in the Theory of Poker near the end. The player who never check raises can be assumed to be weak when he checks.