If you bought your PB in an Apple store, there is a little-known policy that Apple has regarding replacements: They are up to the store manager. This means that you can pursuade a store manager to replace your machine and that store would receive credit for the machine, making the swap easy on the manager. Nothing goes further in life than standing in a crowded store and talking at a normal tone, with customers around, about a defect with that company's product. Say "only two weeks old" and "warped case" and "I paid $xxxx for this thing and I expect it to be in perfect condition so long as I have not damaged it myself only two weeks after I buy it". Be nice, but firm, and be around other customers, so that the manager has an interest in making the store, and Apple, look like they care about the customer and their products. Companies need to stand up for their products, and I think Apple will. Saying "aluminum warps" is not good enough. There should be a disclaimer on the box when you sign it that says that, if they want to fall back on it as an excuse. If not, they should not make the products out of materials that do such things. Aluminum is nice, but if they are going to say "well, it bends...didn't you check the properties of the metal we use before buying this thing?", it is better left being used to make planes and food-wrapping foil.
Go visit an Apple store.