I was at an event at MIT with one of Watson's designers as I watched the show. I asked him about the 20s thing, and he said they talked about it when they were

I was at an event at MIT with one of Watson's designers as I watched the show. I asked him about the 20s thing, and he said they talked about it when they were designing Watson but they figured the scenario wouldn't happen where another contestant gave the wrong answer and Watson gave the same-but-different wrong answer. Edge case!