Talk about a thread that's gone out of control! We're now talking about the science of injecting a fruit to be used as a weapon!
The man wants to bring a pumpkin on a plane and the real question is whether this can be used as a weapon to injure people or bring down a plane. It's sad that the TSA rules aren't clear, and even worse, each TSA person enforces them based upon whatever mood they're in that day.
I say bring it to the airport and pass it through security. If the TSA guy there doesn't like it, ask for the manager and then cite the "fruits are allowed" section of the TSA website. And yes, it's a fruit as it has seeds. At that point, it's a black and white issue that the government has no legitimate reason to bar it from going onboard. Then it's up to the airline as to whether it meets size regulations.