Bit difficult, that. Let's just say my name was Andy Smith and I was a heinous criminal. I apply to join the party. I pay my money, fill in the form and whoom, I'm in.
Does the local party secretary say "oh, there was a guy with that name who did a thing, what if it's the same guy?", or do they join the guy up because it's a common enough name and new members and that? And when it emerges I am the baby eating cannibal of old Droitwich town, they suspend or expel me?
By the way, it wasn't Droitwich. It was Bedworth. And you can't prove nuffink.