Stupidity: And the end, after sliding to another world, the group is caught on film by someone in her house. Quinn goes (illegally) into the home to get the tape. There is no point to this. Throughout the series, many people have seen them arrive, or leave, and usually when there's a mix up with one of their doubles, they spend so much time trying to convince people they are in fact from another world but can't prove it. Quinn doesn't even bother to see how long they're going to be on that world first.
Stupidity: Throughout the series, people in the group always say they need to stick together and only separate if absolutely necessary. Here, Quinn and Rembrandt take a vacation pretty far away from Wade and Maggie (they had to fly to their destination). And they do so knowing they have no way to directly communicate with the others (i.e. cell phones) in case something goes wrong, which it does. They get bumped from their flight, but it might have been easier to get Wade and Maggie to fly to them.