I ordered an iMac G4/800 from Mac Mall back in '02. There was a rebate and a free printer offer. When everything arrived, I had also received a USB cable which I had not ordered. When I called them, they said it had been automatically added to my order because the printer hadn't shipped with a cable, and that their customer service rep had surely informed me at the time, so I must have been mistaken.
I politely informed them that I had not been so notified, and that I did not need the cable since I had one already.
They said they were going to issue an RMA and have me send the cable back. I got the $14.95 or so credited to my card, but never got an RMA. Still have that cable somewhere around here.
Since then, I always order directly from Apple or go to an Apple Store. Not that it was a horrible experience, but it bothered me that they would assume I needed something and just add it to the order.