The AccuVote does not see headers. I might not be following what you mean here though.
No, but it is an interesting question. Right now, the only options are to return on blank race or blank card. For the version 2 AccuVote, we will also support rejecting on a race-by-race basis, to handle the so-called pollworker initials race. That is not quite what they want either though.
Certainly it would be possible to create a flag to reject on blank side, although my gut feeling says that keeping it simple outweighs the utility here. Could be convinced otherwise if a lot of people really want to see this though, or if Travis wants to pay for it.