It isnt just direct water either! Corrosion of components can be caused by condensation and sweat! How many women keep their handset in the kitchen whilst cooking? Whilst Men tend to keep them in their trouser pockets, especially whilst out, for instance. The corrosion can take months to affect the phone. Insurance is generally reccomended as certain policies now cover liquid ingress! As for them being mobile, handsfree will help. If you should take a call when its raining, all that will be open to the rain will be your handsfree set! Cut the risk youll cut the chance of it happening again!
Can I just point out to everyone that I can't think of a manufacturer who repairs their own phones in the UK, they all use service agents to do it for them. Why do the service agents do it, they get paid to do it! It is not in their interests to reject a phone for liquid ingress as they wont get paid so why would they not do work that would earn them money? They only reject the repair because they know if they try and repair it it WILL come back again and cost them money. How that liquid ingress got into the phone is another matter. It only requires a very small drop of water on the outside of the phone to "suck" into the main board by capillary action and wreck it. If you look at all phone instructions it tells you not use the phone in any situation where it may get wet. If your phone does get water on the outside dry it straight away.