My girlfriend spilled salsa on her 3GS at the weekend, so each time you press the button now it squelches. lol
its 100% humidity related.
As any replacement from Apple would be a reconditioned one, I take it these are just peoples old phones checked over/repaired. Call me a snob, but I'm trying to decide if I want my perfect (apart from this fault) iPhone replaced by one sneezed on by someone else.
I think i'll suffer a bit longer, as the fault is a bit hit and miss really and I can guarantee it'll be fine when an Apple geek touches it.