This is partially due to liability: if someone slips on a wet spill and hurts themselves, Whole Foods is liable if they haven't been taking reasonable measures

This is partially due to liability: if someone slips on a wet spill and hurts themselves, Whole Foods is liable if they haven't been taking reasonable measures to clean up such spills in a timely fashion (1/hour). Scanning is a way to later prove that such cleaning was happening.