Good points & glad to hear everybody feels the same way. I've been really fortunate to hunt with several good friends over the years (thanks JohnR, countyhunter, Beentown), both as a guest & a host, and we all have the same position on spots. Even public land spots. Legally, public land is public land, and anybody can hunt anywhere they want anytime they want. But there is an unwritten man law that says if somebody takes you in someplace, you don't turn around and show up there without them on your own. It's just something you don't do without first talking it over.
The way I look at it, I was a newbie once upon a time & had some guys invite me out to hunt ducks. Years later I've been continuing to return that favor when it's possible. At the same time I'm still hunting with one of the main guys that introduced me, and always look forward to it.
