Please tell me I'm doing the right thing...

Tonight Micah put his pull-up on to get ready for bed. Then I heard him mumble something about having to go to the bathroom while he was standing in his pull-up in the living room. I looked over and just knew... "Did you pee in your pull-up again?" I asked. "Yeah," he said with puppy-dog eyes (That DON'T work on me when he does this). "Go, take your pull-up off and wash yourself up. You're done with pull-ups." I said. I wasn't mean about it, but I'm done with his little games (peeing in his pull up to "try it out," telling me he doesn't have to go before bed and then getting up to go 5 minutes after we tuck him in). I know that for some boys it takes until they're like eight or something, but I am convinced that when he pees, he is awake. I believe that he's just lazy (I know that sounds harsh, but I really do).
So... here's the plan. He's wearing underwear tonight, and I fully expect to have to get up and clean up once or twice, BUT I'm going to have him help me take the sheets off, etc. I'm hoping it will convince him to acutally go to the bathroom before bed (He tells me nothing will come out when I know he hasn't gone since 3:00 or so), and then maybe I can find out if he really needs a pull-up for the rest of the night or not.

F.Y.I. I don't function with lack of sleep (like you didn't know this already).