It would be so easy to vote twice. I don't think precincts do any cross checking. I could be wrong, but the systems are so antiquated I doubt they do it. And it would be relatively simple to do.Wonder how many of those purged were voters who had moved and temporarily were registered at two addresses with the purged registration being the old address.
Was a ward chairman many years ago. Had a great many apartment communities in my ward. Apartmemt dwellers tend to be highly tramsient so voters registered in more than one polling place was common. The potential threat of course being they could vote more than once.
Neither party was overly concerned about someone actually voting twice. Our focus back then for both parties was getting people registered and voter turnout, not purging.