MacBook :: Oversensitive "A" Key - Slight Touch

Just got the new 2.4 MB out of the box, started to register and discovered a rather annoying glitch: an over-sensitive 'a' key. The slightest touch is enough to set it off, I mean a feather touch, nowhere near a full key punch. Makes typing a real paaaaaaain. Anyways, rest of the keyboard works fine, so I figure gotta be a wonky contact. Checked out a few help forums and videos. Tried propping it up with the stiff paper trick. Still no dice. Popped the key lid off, exercised the plaaastic connector bit, which seemed fine. However, the rubber/silicon 'nipple' (the impact point) was also extremely sensitive. Moving swiftly along and ignoring the reams of 'sensitive nipple' comments, I popped off another key to compare. No sensitive nipple issues there. Now the question: what to do, what to do? Tried the Mac store, they kindly offered to take it off my hands for three weeks. Seems a bit much for one measly key.