I never dropped my Wii or anything but I have been hearing a lot lately that more and more people are experiencing a problem. The shipping idea is probably true as Nintendo told me not to ship my Wii back in the same box I bought it in as, and I quote, "it is not durable enough to ship in".
Nintendo had no problem shipping me a label. They set up the label ship first and then they asked me what was wrong with it. Weird they didn't send you one, what kind of problem did you have?