you never spilled water on it? I use a damp cloth to clean my track pad. Maybe occassionaly I have put a some drops of water on the track pad then wiped with a micro fiber cloth. There should be NO reason why any of the water sensors should have gone off. I recently bought AppleCare, and have this paranoia that when if I need to use it in the future they'll say "Oh the water sense is off you wasted your money on AppleCare"