I'm shocked! - "wont do a repair as it will break the water proof seal on the unit"? I could understand this if you were taking it to a third party but Garmin??? That really is poor service!
I've always had really good service from Garmin, that's one of the reasons that I keep buying their products (705, 800 and 1000 so far). But, if this is the way they're going to be dealing with their customers then I'm afraid they'll lose a lot of customer brand loyalty.