The mystery might be solved. The other morning, I was getting ready for work and Brian walked out of the bedroom with the cat, who had just jumped into the bed. I went to the kitchen and the gate was still locked. Brian put the cat on the other side of it and then the cat walked through the slats and back into the kitchen (he was too fat to do this before). So, that explains one thing. But, why the gate would have been open two days this week remains a mystery–unless Buster was trying to get away from the cat and went downstairs. That is the only reason I can come up with so far. But, we won’t be pondering this for long because I’m going to order a new gate this weekend. It will be both cat and dog proof.