My 5 yr. old boy is totally trained during the day, but during the night he is still supposed to wear pull-ups. Some nights, though, he decides to take them off and exchange them for underwear. I think it bothers him that his 3 yr. old sister is dry at night but he's not. He will wet the bed and not wake up until morning-- hours after the accident. After doing this several times, I have started checking for his pull-ups every night after he falls asleep to make sure they're on. But, yeah, really gross.