A lot of river permits don't allow the WAG bag system... Westy, Yampa, Lodore, Grand, to name a few. The regs on those generally state 'washable & resuseable' which it is neither.
"Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover." - Mark Twain