Having spent some time in retail, customers have been told "they're always right" and act like it. Such that it's difficult to differentiate between the legitimate problem, and the person making a scene if they don't get their way.
Some time back I was in a Tractor Supply store looking to pick up a chainsaw to keep inside our camper. A guy was looking over the saws and was checking out the Poulan pretty close. He asked me what I thought and I suggested he at least consider the Jonesreds as they were better saws - he said it didn't matter anyways as "he was going to cut down the tree and return the saw afterwards", with a laugh. I said "That's pathetic this isn't a goddamn rental joint". He quickly walked off, but the buy/use/return phenomenon is more common than thought.