Re: @Bernard M. Orwell
Yes, let the fraudulent votes stand. I don't know how many are doing it now, but if the government announced a process for checking for duplicate voting I expect the number of such duplicate votes would be tiny. The vote count errors from stuff like scanning problems or human error like displaced ballots would be quite a bit higher than from double voting.
Trying to achieve an EXACT count is a laudable goal, but it is only a goal. Certainly you can't create the possibility of linking votes to individuals just to solve a problem that would add 0.00001% error to the count in a state like Florida.
If someone wants to pay for extra votes by going to prison for a couple years, be my guest :)