Wow, this is a new one... I can't tell you about pumpkins, but I can tell you that it's dicey carrying on bowling balls, which is about the closest thing I can relate to this. Sometimes TSA declares bowling balls must be checked, other times they let them go through. I think you have hit the nail on the head, though. The real question is does a pumpkin contain liquid and I think the answer is no. I'd say go for it.