Well we know he don't give a shit about anyone but himself, so he can sacrifice a few his dumber supporters and he will be okay with it.If they do this under their own names, they get caught, the vote gets thrown out, and they may end up losing voting privileges. The can try to frame someone else, but if they do it in person and taken into custody, that's their ass.
Let's them believe his ass and do it tho. They will stop believing that voter fraud nonsense from then on.
Besides, knowing him, he will find a way to pardon some of them. If not like he cares about the rule of law.