I have personally had more than one housing flood, and been in the water when a few others have flooded.
The first time was probably due old o-ring (with help). Took a number of pictures of a whale shark early in an 80' wall dive, but while switching from P to MyModes I accidently stopped at M, which resets to 1/1000th shutter when changing batteries. Those images were black, which caused me to review them many, many times (what went wrong?).
At the SS the dive leader wanted to see the pics so we were reviewing the series of the whaleshark, including the black ones, when I noticed water entering. I was near the end of SS, after a not pushing the limits dive, so I ascended as quickly as prudent. It's possible that all the reviewing at depth heated up the interior, so expansion pressure popped the o-ring out.
All the other floods I have experienced or seen have been at the start of the dive, and except on a deep solo dive where I would plummet as fast as possible, if you are paying attention to your camera you should see that it's happening before reaching 33'. A clear housing is also a pretty nice feature!
Being waterproof is the best feature of that line of Oly cameras; without manual settings and without raw images the waterproof-ness is almost the only redeeming feature IMHO. The other feature I like over the SeaLife is that it is a compact P&S for above water shots as well.
I personally can not recommend any camera that can not do raw and manual.