As one who has been hunting public land for many years, there are many different opinions and ideas about how this should work.
After scouting out an area, which may include hacking out a trail to get to the area, as well as trimming up shooting lanes, any hunter would hope that others would respect that effort and not take advantage of hunting the exact spot. Yes we may hope, but it is still legal for anybody to hunt anywhere whether or not they actually cleared the area. Therein lies some of the controversy.
I try to find the most remote, out of the way areas to hunt, but I have learned there is almost always someone else who has thought of or found this place before me. There aren't really any "secret" spots. It can be really frustrating to find a great area, and then upon closer inspection find a couple of stands set up at the exact best spots.
So do you forget about that spot and move on to another? Usually I do, because for one thing I don't want the other hunters walking under my stand to get to theirs or vice versa. Also I do respect hunters taking the time to scout and find an area.
But what do you do in this situation? Guys set up stands at the best spots on a small island on public land. Funnels, rub lines, scrapes, etc., are there, and the stands are placed on the first day of the season? If it is a productive spot, the hunters may leave them there for all four months. Or they may only be weekend warriors and hunt their stands a few times all season. Do they then get to basically block the island for the entire season? In my opinion, hunting on public land is a day to day venture, not a season-long "this is my spot type of deal."
While most WMA's are pretty large in area (Sherburne WMA for instance, is around 44,000 acres) not all of that is huntable or even feasible to get to. So when you have a small area that is desirable, two or three hunters with well-placed stands can effectively block off a nice spot. You will either have to walk under their stand to set yours up or find another area.
I can remember many mornings at Sherburne when I had been up in a tree for 30 to 45 minutes before daylight, being totally silent and the light is just getting good enough to see. Suddenly you hear a distant crack, then another. Your heart starts to pound, only to be quickly deflated when you see that flashlight shining through the trees and you know it is just another hunter coming in late and spoiling every bit of quiet and solitude you have created.
Ah the joys of hunting public land.
It got so bad that, every time a heard an early morning crack, I assumed it was another hunter and would sometimes be very surprised when it actually turned out to be a deer.
Another time, a hunter walked in right at primetime in the morning, coughing and calling in a loud whisper, "Dave, where are you? Dave, I'm lost!" He actually walked under my tree and apologized, but kept up with the "Dave where are you?" It is now funny as heck, but at the time, believe me I saw no humor in the situation. By the way, that morning within 30 minutes after the guy passed my tree, a nice doe came out from the exact direction he had walked in. Go figure!
My advice on trying to secure a spot that you want to hunt on public land is to look for the difficult-to-reach places and keep them that way or at least maintain that appearance. For example if you cut a nice, wide trail into a thicket, the next guy is coming in right where you cut, and if it looks good enough he is probably going to throw up a stand right there.
Now if you didn't cut out the first 10 feet of that trail, chances are he never sees it and goes on to the next more easily accessible area. Another tip is to use bright eyes instead of flag markers which everyone in the world can see in the daylight. If you do choose to use flagging, making some false trails that lead away from your area can also be quite effective – if done right.
In short, if you want privacy on public land, you have to devise a strategy, become creative and work for it. It can be done, as I have been very fortunate to hunt areas with virtually no disturbance whatsoever for an entire season. But it did take a lot of work and planning. To me strategizing the area you hunt, as well as how, when and where the deer may come in, is a major part of the fun of hunting.
Good luck, be safe and have a great time!