Regular people who check in the dark have small/medium pairs. FACT! They either hit their set or they don't.
I agree that checking in the dark is a dumb move, but your oppo is generally just trying to be cocky. If you bet in the dark you will win the cocky game and make some people laugh. This would be a good start to the hand. Of course, if he raised dark he would then win the cocky game himself, and would probably deserve to as well. But I've never seen anyone do this. Betting in the dark retains your impetus in the hand and doesn't allow your oppo to negate his positional disadvantage. But don't let this stuff boggle your mind. It is actually all very bollocks. Last night we were down to 2 tables and there were two dick wavers who both agreed to go all-in blind next hand, so I raised UTG with

. They both then decided to look afterall, and folded. But only after another guy not in the hand called the TD over to rule as to whether the all-ins stood. Now that guy was a idiot.