In some cultures, it was rude to pop up in someone's home uninvited and unannounced. It was especially bad to bother a tribe of isolated people, as things could go horribly wrong.
This island in the sky was perhaps more dangerous than most places, but that didn't stop Bardeelus. He trotted across the island as if it was his own, because Kaya was with the team, and she backed them up!
Bardeelus worried about other things instead. The last time he made a deal here, he unknowingly ended up getting married! It's not that he didn't want to end up with a second wife (who he'd be too afraid to touch), but instead, he just didn't want to get embarrassed again.
"Those old bastards gonna want something, I know it! Went through bull-shit and a half to get a couple of their people down to the university… can't imagine what they'd do to protect their secrets?" He thought.