I don't think it is ridiculous to charge for more hay/bedding. Left to their own devices, many folks will over bed stalls to a ridiculous extent. And overfeeding of any foodstuff leads directly to more use of bedding, so that is a 2x scenario.
The people I know of who have hard limits of 'your board includes THIS much hay and THIS much bedding' are the folks who are running REAL businesses. And likely not getting $ out of boarders for lessons, shows, etc. So they alot so much/horse and if you want more you pay more.
Overall though, I have to say most people just WANT more. They don't wanna pay more for it!:D:lol::winkgrin:;)