I'm not saying you should do this but...
http://appleinsider.com/articles/15...-the-shower-and-swimming-pool-ultimately-fail
Yep, and the first of the sport watches that Consumer Reports did an IPX7 test with failed, but the next two passed with flying colors, so they just wrote it off as a fluke.
Some will be better than others. You have a link above in the thread that a reporter was told directly by Apple to not swim or shower with it. (That someone overheard a conversation of Tim's matters not - he didn't say that to the press).