Pete,

that was my logic for a long time too. But things do happen. My water bottle can get lost, empty, or I forget to refresh water in my canteen. I have the prepackaged water under my seat and I know I'm good until 2005. It just sit there in case of emergency. I still do things the same way as far as regular half a liter bottle on my hip or in cargo pocket goes. But just in case my spare prepackaged water is there if I need it.

Matt