because the odds of three people matching everyone in round one are so tiny that you wouldn't plan for it
Even if the chances are tiny, I would think you still plan for it, rather than get caught flatfooted. Maybe on one day the question order gets mixed up, and it isn't noticed until they progressed too far.
Although it wouldn't come cheaply by any means, they could discard the round and start over. I know there's a Press Your Luck episode where they ran a disclaimer that they ditched a quick dud of a round.
Another option could be that they just blow a fuse like the old days, and play Rounds 2 & 3. Even if it is provided for in the rules, Gene could play it off and ask the players if they would mind playing the next 2 rounds at 0-0.