I have been warned, and after three years of racing, I was finally kicked in the nose during the swim. Surprisingly, it didn't hurt at the time (later on the bike the pain set in), but as soon as it happened, I got a massive cramp in my calf. It was as if there was some sort of panic response. It has been a couple years since I cramped during a swim, and increasing my salt and water intake prior to swimming took care of that, so I don't think it was coincidence.

I am curious if anyone else has experienced this.

On a side note, I made the mistake of telling one of my cycling buddies about the experience. He has been trying to work up the nerve to try a tri, but is terrified of the swim. Now he will probably never do it.