The whole point of protesting the voting machine irregularities is that it's so easy to cover up your tracks when cheating. These machines seem to be intentionally designed to have multiple "back doors" that could easily allow tampering without detection.

Any evidence of wrongdoing is just a bunch of ones and zeroes that are erased in a fraction of a second.
Poof! Like it never existed in the first place.

With real paper ballots, there's always a chance of fraud, but much harder to pull off. It would require manipulation of physical evidence that always leaves some kind of trail.