@lock you basically said about that hour thing, so now that any self voters read this, the only thing thats stopping them is the ip stuff. sorry to ruin the moment, but just a word in advice so no one gets any "ideas" to pass through the banning.
We know that. There's nothing else we can do. Everyone knows about what IP addresses are and such. It's a common thing.
Then why don't you make the upvote button blocked when you use the other account from the same IP that you voted on it before ? that way no one will be able to do a multi vote again.
Two TPT accounts from the same email can be detected other than that I don't know but just for extra protection even though anyone who will do that will get banned.
In total, I have about... 1... 2... 3! I have about 3 alternate accounts. 1 is floating around somewere, I forgot the name, and the other two are perma-banned :P