I don't think that has anything to do with it. I think saying "iPad" is a bigger draw for crowds. And they were typically just gift cards, which means the money will end up getting spent back in the store anyways, probably on accessories that cost the stores next to nothing, and you'll end up spending over the GC anyways typically.
I don't know how well the Surface sold. I strolled in to my BB at 3pm to pick up the mSD card for my Surface Pro and they still had RT's. They were even price matching Staples $250 with touch cover. Staples in my area supposedly still had them as well, but I didn't go to verify.