Great in depth post. I hate seeing the trash in the wild and when I take my kids fishing, hunting, or hiking we always pack out more trash than we carry in. It is a small thing, but I can't look at all the trash and do nothing. Those pictures of the river bottom are just horrible.
However, New Braunfels (and for that matter every other city in the US) doesn't have citizens. You are residents, but we do not have city states. I do think if this ban stands up in court you are likely to see a serious dip (sorry for the pun) in tax receipts. Perhaps there is a way to institute a check station and make people responsible for packing out what they bring in. Yes the lines would suck and the innocent would be punished with the guilty there, but the fines/fees for missing containers would be borne by the guilty/irresponsible. This could also be a good way for local law enforcement to identify potential DWI offenders...