No diapers, please

So, lately we've been having issues with our 2 year old taking off her diaper after she goes to bed for the night. Some nights when we check on her she's completely naked, some nights it's just the jammie bottoms that are off. For about two weeks we had no problems at all. Tonight, when I checked on her, I noted that she was fully clothed and I was pleased. Then I noticed the diaper lying next to her on her bed. She has gotten so smart that she now puts her jammie bottoms back ON after taking off the diaper. Now if only she would just use the potty!