This is an element of any confrontation we all hope to avoid. I carry a stainless revolver when fly-fishing the stocked trout stream a few counties east of me, mainly for snakes, with the first three rounds in the cylinder being Rat/Snake shot. While wading down-stream I encountered two "gentlemen" riding four-wheelers up-stream. The pistol was prominently displayed clipped into the top of my life-vest, and as you mentioned the conversation was VERY polite from the beginning. They both thought my suggestion of them getting out of the stream and continuing their trek on dry ground was a good one.

I hope every situation of someone claiming "my spot" can be handled pleasantly, but understand that there are some who do not hold the same opinion of the situation as most who have posted here.

I think the suggestion earlier of taking a cell-phone picture of the boat registration numbers and letting the authorities handle any differences is a good one.