This is Greg from AngelHack. We have nothing to do with said "shell" accounts, nor did we give anyone incentive to make shell accounts. We offered our community free tickets to our next event if they helped us with up-votes (our definition of a successful product launch).

There was no incentive to vote more than once. But like with any community, we have our more passionate users that go above and beyond to try and help us succeed. It looks like that is what's happening here.