I took this picture and sent it to my wife with the caption, "Uh, maybe I won't go upstairs right now."
Then, a few minutes later, I went back to the steps, and Inky was gone, but our dog was laying across a step. I told my wife that the guard's shift must have ended.

Yeah, thanks. He's so skittish that I bet the mechanism would scare him off. :( It really doesn't take much. Plus we'd need three - he can't have the food that the other two eat, it's not approved for young cats.