Our boxes are in the basement, so there is a line going up the stairs. I do agree, they wait until you are in the middle of cleaning, and then they have to go.

I get the biggest kick out of Mystic and Abner. They are allowed outside, they do most of their business outside, but the moment they hear me cleaning their boxes, they are pawing at the back door to come in and do their business. Must be something about having fresh litter run between their claws.