tjw37909--The situation you describe (and two others on the thread) is precisely why I try, when possible, to get back of beyond. There's much less likelihood of such situations, and if they don't happen then I don't have occasion to open my pie hole (which I will invariably do).
I've encountered this time and again, with one calssic being this past summer when a fellow splashed into the stream directly in front of me and began casting. I walked up to him and asked him what he would think of someone doing the same to him. To my absolute amazement he said: "Don't you fish that run in front of me. I want to fish it."
I then pointed out that these were public waters and I guessed both of us could do as we pleased, but that common sense, decency, and sound ethics dictated giving the guy who was there first elbow room.
He then said I couldn't fish the stream (this was the state water on Deep Creek) where I was at all because he owned it. Apparently he did have a small lot fronting on one side of the stream, but I pointed out that he didn't own the water and if all landowners had an attitude similar to his the NCWRC would no longer stock the fish he was trying to catch.
None to this sat well and I eventually just reeled in, told him to give a bit more thought to what I had said, got out, and walked upstream.
It was a memorable moment, but not of the positive kind. My basic view is that the best we can do is set a good example, say something if the situation seems appropriate, and avoid heated confrontations. I must admit the latter sometimes is a challenge for me, but as I age I'm getting better.
Interestingly, and this will possibly stir some controversy, the prime examples of poor stream ethics I have seen come almost exclusively from one of three groups: (1) Old-timers such as the guy above who somehow think they "own" the stream. (2) Young hot shots who are new to the sport and have all the equipment but none of the ethics or appreciation of the fact that there's more to fishing than just casting and catching. (3) Spincasters and bait fishermen.
The latter may seem elitist, but I'm simply stating what I've observed over the years. I would add that certain segments of the fly fishing community can be snobs, and I don't frown on spincasting or bait fishing. I don't do either but I have, they are legal in some waters, and they are effective. Also, a couple of the finest fishermen (and men) I've ever known were, respectively, a spincaster and a bait fisherman.
Now, I guess I've opend a can of worms (yep, pun recognized and intended).