Slave Island - S1-E7
Stupidity: At the beginning of the episode, Pyro is among the Genoshan prisoners, and he is wearing his flamethrower device. While his inhibitor collar will suppress his mutant power of pyrokinesis, he can still use the flamethrower itself as a weapon. This would be akin to a prison allowing an inmate to walk around with a loaded gun. (00:02:12)
The Tale of the Dream Girl - S3-E10
Stupidity: A boy walking through the bowling alley stops and lets Johnny pass, even though Johnny is supposed to be a ghost no one can see.