The other hypothesis is that the actual ballots were tampered with.

Black Box Voting : 1-17-08: Ballot boxes found slit; NH stops putting ballots in vault;

No worries, say New Hampshire officials when cuts up to eight inches long are spotted in newly delivered ballot boxes. "The only seal that counts is the one on top."

Except the seal on top can be peeled off without leaving a trace, then reaffixed.

Black Box Voting has been doing a chain of custody exam for the New Hampshire Primary's recount. On Wednesday night, Election Defense Alliance's Sally Castleman mentioned a troubling observation: After following the ballots back to the ballot vault following Wednesday's recount, she had the opportunity to enter the ballot vault, and noticed what looked like cuts, or slits, in the side of many ballot boxes. New Hampshire officials assured us that these cuts, which slice through the tape and seals do not permit access to the uncounted ballots, pointing to a label on the boxtop which they call a seal.

Drew pointed me to this page.

We have met the enemy, and he is us — Pogo