New to me.
I got chased around the Sam's Club store today by a king sized Roomba. It was a full sized scrubbing wheel / squeegee that had a seat and steering wheel but no driver. The store was open but not crowded, and every time I went down a new aisle, that sucker beat me to it.
Whenever it got to a shopping cart traffic jam, it just stopped and waited until someone moved. It waited patiently, but next time I go, I will not be surprised if it honks and says 'keep moving people, I'm working here'.