That's a very good point, jimmy, and one that I've considered, too. Hunting is a game where sound can kill your chances, especially an odd sound. Now, for waterfowl and upland birds, this isn't as big of a deal unless you fire up the camera as the birds are right on top of you (not possible to know with upland game and highly unlikely with waterfowl). But, with big game, where it doesn't make sense to have the camera on full-time, a tone at startup when the critter is approaching asking for trouble. I'll let you know how that works out with the Replay XD, fo sure.
Also, just some food for thought on where to mount the camera: note that I used to use a set of H-S iKam Xtreme's last season. While the video quality on those is sub par, I found that having the camera mounted directly on my head was perfect for virtually all hunting situations not involving a scope, especially duck hunting. I'll have to post some YouTube clips from last duck season so you can see what I mean. You may have some issues the limbs on a bow getting in the way of the shot, but once you release, you will at least have a steady shot. I'd at least look into some sort of headgear mount for whatever camera you choose.