I hunt on public land. I think it's just hunter's courtesy not to hunt another's spot. Some of the guys we share the deer woods with I only see one or two days a year, but we know who they are, if vaguely, and where they hunt. I feel that public land is just that. Anyone who wants to know about it can and should.
As far as inviting other forum members on hunts, I would at least make sure I have interacted with them on the forum, email, phone, ect. You can get a feel for them prior to the hunt. They would get treated just like any other hunting partner: break the laws/safety rules ONCE and you're gone. I'm suprisingly NOT synical about this. I feel that 99.9% of hunters are lawful, ethical, good stweards of the land. That being said, anyone who wants to hunt upstate NY, let me know![;)]