Young lad on a hike fell into a freezing lake and he was the one carrying the phone. ( yes there should have been two phones ) and it was used, still in condom to call for help.
There was a study done on mobiles and they concluded they carried more bacteria than toilet seats: maybe condoms would be useful on everyone's phone, not just for waterproofing.
That gadgetshow on Ch5 did a waterproof test on a 5140, they submerged it in about 6 inches of water, then took it out & left it for about 5 mins & it worked fine.
Can confirm what Snico has posted - the JCB phones are pretty good. Mate of mine works in a quarry and so uses one of these - it even bounces - literally, you can throw it on the floor and it almost bounces high enough to catch it again - and its completely fine after...