Beyond a Reasonable Scout - S5-E3
Other mistake: Phil the Scout ties a rope to Mikey's see-saw end's handle to lower Gus down without hurting him. Couldn't Mikey just climb off and hold the see-saw down with his hands and lowered Gus's end down slowly?
Suggested correction: Well, yes. He definitely could have done that. But I'd say that this belongs under stupidity, as they are defined as "stupid annoyances, like daft character behaviour," and this falls under that, to me. It's not really a "mistake" of any kind.