Still easy to slip in paper ballots for counting, unless papers are specifically watermarked and kept a complete, highly guarded secret. It most likely would not be as easy to impact elections as much though, where in the past the machines flipped numbers. If the Federal government started withholding funds to states that did not abolish machine voting, you can bet that election integrity would happen sooner rather than later. In addition do same day voting and only military and truly home bound can vote by mail in or absentee ballot.