"Both [customers] Keneker and Pittman use their iPhones at the gym to listen to music or use the calorie-counting fitness applications that actually come with the phone. They said Apple employees told them their sweaty palms are the likely culprit here."
There are no calorie-counting fitness applications that "...come with the phone." Sure, you can buy them in the App Store, but they're not built in. Also, Apple just so happens to make an iPod that was designed specifically as a workout accessory and it costs less than $80US. My guess is, if you can afford an iPhone, you can swing a shuffle -- or a case that blocks the dock port, which is a pretty accessible area for moisture.
I know it sucks to have your sweet iPhone ruined, but this was completely avoidable. Plus, aren't most phones with cameras banned from gyms?
All right, folks. Perhaps I was a bit too snarky. The lesson here is twofold. First, the iPhone is quite sensitive to moisture. The water sensors are placed towards the device's extremities, so even a sweaty palm can trigger them.
Secondly, with that in mind, be careful when using the iPhone in situations that may introduce liquids. We recommend a low-cost case. --Dave.