The problem is, if you vote for candidate X, there's no way of checking if your vote was really computed or tampered with by the machine. The report will print something like 'candidate X = so many votes', but beyond that you can't know if that number was altered. If you had individual printouts on a ballot along with the electronic vote, you could have the ballot counted, and know.
What if some wacko starts claiming he accessed 50 voting machines and altered to switch 20% of votes for cadidate X into votes for candidate Y, as the votes are being cast? How do you check?
