Great thread Milo!
Fishing is about more than just bringing a fish home. It's about being outdoors, seeing the changing seasons, the lifecycle of the salmon, etc, etc. I think we often are so focussed on catching a fish we forget to enjoy the experience.
I notice from the comments that the fishermen that don't seem to get riled with the Vedder do a lot of exploring and probably don't stand with the crowds of people.
As far as the lack of ethical fishermen, although there are some of them, most of the fishermen fishing "unethically" probably lack the experience to do the right thing. I'm not sure what's the best way to educate these folks but one at a time as we come in contact with them is probably the most practical.
As far as the truly unethical fishermen, keep phoning them in! With enough phone calls the fisheries officials will show more of a presence. Having more people out on the Vedder fishing is a good thing, as it draws more attention to our sport and that makes the politicians take note when they make decisions about the management of the resource.