As a prior, I would consider submitting lots of extra paper ballots to be much weaker than manipulating electronic voting. (To be clear, I think the prior on both is fairly weak.)

Project Veritas is not a credible source.

Edit: It seems like HN has gotten a lot more Trump and conservative since the election. I should hope that reiterating that submitting thousands of paper ballots of a lot more complicated than hacking into a computer system is obvious.