You will find these kinds of people on most any popular river.

I have had guys try to run me off certain sections of my home water by faking that they were calling someone who they said gave them sole rights to fish this section. I just laugh at them and tell them to get them down here and we will have that discussion face to face. All the time knowing I got permission from the people who actually own the property and have already checked in with them that morning.

That is pretty much where it ends, then they go stomping off in a huff because they got blocked from poaching on private water...