Thanks guys.
David, I think you are right. I get the impression that as long as you aren't in a torrential downpour, on horseback, running around, or in danger of being turned upside down there is no real downside to an open top pouch. Plus they look really cool in my opinion...
I could see this type of pouch being really handy for the local woodswalk and line shooting matches that I go to around here.