I had the same thing happen to me, but I was traveling. I have a 3 year AppleCare plan, but the "Genius" told me it was accidental damage and so not covered. When I challenged him, he pointed out some surface scratches stating that this confirmed his assertion.
If you lose the rubber feet he claims that Apple do not carry spare rubber feet. So you need a brand new backplate for the laptop. They will apparently cover the labor, but as in their opinion this represents accidental damage I am liable for the cost of the part (which they didn't even have in stock).
I am amazed that they don't carry spares, and seriously claim it is accidental damage requiring a new backplate. If anyone knows where one might obtain a rubber foot I would appreciate pointers...