IMO...

NEVER hunt out of another person's stand without permission.

Also, public land is "first-come-first-served", but that does NOT mean that people get the right to stake out their own little areas like it's private land. To do so is like telling people that, it's public land, but only YOU have the right to hunt there. Not so.

We go through this problem at our sportsman's club every year. Some guy likes to plaster the whole woods with treestands, and yell and complain when anyone hangs one even within eye-sight of his. Even if he's not in one of his stands, he doesn't want anyone else hunting the area.

If a he's not in his stand...too bad, it's public land. Hang one in another tree nearby and hunt. Take your stand out when you leave (to avoid potential problems). If he shows up while YOU'RE hunting and gives you a hard time, remind him what PUBLIC means.

JRW