Somewhere on this forum I believe someone posted a depth rated container that would hold the spot messenger perfectly. The messenger itself is waterproof to about a meter, just not to depth. You could keep it stored in the container for the dive, then if stranded on the surface, you can pull it out of the container, activate it and still be able to use it to get a signal out.. Not a bad little device, One of the folks in our local Jeep club picked one up recently and used it to track a trip. Considering some of our offroading trips take us several hours, minimum, from cellphone coverage, and even out of 2m radio repeater coverage, not a bad little device to have especially since I could use it on ocean dives too.
The old saying applies... Better to have it and not need it then need it and not have it. It seems that there are a lot of topics on here about divers being swept away, hopefully technologies like this can become more wide spread and at least mitigate losses where the diver(s) aren't hurt, just swept away by current. Given the cost and risks of diving in general, the price for Spot isn't too high.
Edit: Just to add, I'm not sure what else is out there for personal locaters, so there may be a better option.
