I hunt public ground and I've seen plenty of confrontations; even had a couple myself. I have a special place in my heart for the #%@$&'s who act like they own public ground. As far as distance between you and someone else, it mostly depends on the situation and terrain IMO. There lies the problem as you see from posts above, what you and others feel a good distance may be grossly different. I certainly wouldn't set up on the same travel pattern as someone else is. In flat timber I'd give an honest 150 yards, but that's me. 500 yards, that's a stretch, that would exclude all but one person from hunting some smaller public areas.