People were breaking out in laughter at the midnight screening of Attack of the Clones I went to, but it wasn't derisive laughter, it was more like "HOLY SHIT I WAS NOT READY" kind of laughter.
I'm trying to think of a situation that's comparable and it's like - you know those reaction videos of NBA stars on the sidelines at a Slam Dunk contest? That's how people were laughing in that theater.
Yeah, same thing happened in my theater. When Yoda pulled out his lightsaber everyone was confused and laughing and then started cheering.