No More Crib for Me Mom

At 18 months I take my kids out of their cribs and put them into "Big Boy/Girl Beds". I decided to keep William in his crib until he was 2 years old. He thought other wise. I put him down for a nap yesterday and got on the computer to pay bills. About 10 minutes later he comes walking up to me. I went upstairs and asked which kid had gotten him out. It was the "not me" game. I finally decided that someone just didn't want to get in trouble. I put him into bed again and told all the kids not to get him out! He again joined me about 5 minutes later. I then put him back into his crib and this is what I saw:

He is my only child who has climbed out of his crib. I guess he didn't want to be in there anymore. He slept in his "Big Boy" bed last night and it went better that I thought it would.