I'm a Marine Service Tech so I bought this because I'm around water all day, I actually downgraded from a better phone for this one but I'm pretty happy. I mistakenly dropped it in the test tank (about 2.5' deep) at the shop and it's pretty dirty in there so it took a few minutes to find the phone, it was still on, I took it to the sink and rinsed it off and all was good... The touch screen was a little wacky while the screen was wet so make sure you wipe the screen dry before using again.
I picked up a knock off Otterbox type case for it from a Boost store near me because the case I ordered off eBay was taking a real long time and I was nervous about dropping it haha.. The one I bought at Boost was 100% better quality so if you guys plan to buy a case see if your local cellphone store has one in stock first. Also got a screen protector. With the case it's pretty rugged and I'm not worried about messing it up at work and if it happens to fall in the bilge of a boat or something, it's good still.
So in my experience so far, it's pretty damn waterproof haha. As for the jetski guy, I'm sure in some cases, like with anything- it may have been a defective one. I'll probably leave my cellphone on shore when I take my x2 out this spring... No reason to have your phone on ya lol, Do you really need to update your Facebook status while jumping wakes? lol jk.
-Mike