To me the idea it roams the floors and is possibly going to be in the way of people seems to be a major issue. I would think that camera technology hanging from the ceiling or on a track could survey each aisle using simple image recognition.
Walmart - the unexpected champion of the people?<p>Having human workers check for out of stock items when they are walking the store doing things normally does seem a lot more cost effective than the robots I've seen in store.