It's both. Have a look sometime at what customers typically refold and rehang clothing and other merchandise once they've determined they're not interested, and what customers don't.
I noticed a similar trait at Burger King once. Black customers could be counted on the leave their table unbussed while whites returned their trays and dumped their litter into the trash receptacles. Blacks have a corner on the “let someone else do it” market while bitching at how they’re perceived.