Responses to this are interesting to say the least.
While a fairly small plot at 20 acres, it is not much different than what we had to deal with on the farm.
To those stating the OP was an ass, well good for him! I can only assume you have no concept of what it is actually like to own property in the country that for whatever reason, morons see the use of said land at their own beck and call. You have not had to pick up the trash, litter, waste oil, beer cans, and animals these users leave behind.
We had a dairy farm, Holstein's, a fairly tame breed but and it is a big but, they are not always tame and we in fact had a bull that produced well (or he would have been served up at McDonalds) who was mean as can be and would charge instantly, no matter what. There wasn't a straight piece of metal on the truck because of him and trust me, when your truck goes up on two wheels because he caught you from the side you fully understand why you ain't walkin across the open field.
Since they would break the valve instead of the lock on the fuel tanks, we employed the false advertising strategy, put the unleaded sticker on the diesel tank and vice versa. Worked like a charm, typically found em about two miles down the road.
Then there is the knock on the door, some city slicker brought his ultimate jeep down and "thought it was ok since the gate was open" which it never was or the cattle would have been walking up the road like they always do when they get out, and now he is stuck in the back forty. Of course your gonna have to take the tractor up there, drag his lame butt out of whatever trouble he got into when you really need to be chopping silage, mowing, raking or bailing hay etc. When you get there you find out the idiot thought he could do a little boulder climbing and busted his tranny and oil pan wide open and it is running into the spring, so much for the water the cattle drink, how do you like your milk, 10w40 or ATF?
Here is a clue, most folks who buy plots of land do so for a reason, they want to be left alone and whenever they want company they invite em over or go to town. If you stop off at the house and ask to shoot, hunt, swim, 4 wheel, archery or even just enjoy a walk in the woods, they may well become your friend, warn you of the hazards that are on their property and outline the courtesy's they expect to be shown in exchange for the use of the property. Oh and when you think it might be a good idea to go cow tipping, poaching, or chasing cattle with your shiny 4wd suv, the Leupold is actually dead on at 300 yards, that first one is cotton wadding flying out of the end of a 300 win mag, the next one is a boat tail at about 2780 fps, you had better drive FAST.
I can not tell you how many folks have stopped and had a picnic in the "yard" over the years but it is a bunch, the three acres next to the house were well shaded, the site of the old outhouse, mowed weekly because grandma wanted that way and it has a view from an elevated position worth a million bucks. No one was ever refused, some kids even got a tractor ride down to get the cows, got to pet a calf and taste milk from the tit squirted 20 inches.
I would offer that most land owners are very friendly people who enjoy others enjoying their land as they do but are not to be crossed. Taking pictures by the pond, sure, go for it if you ask, walking out there by yourself and making me disrupt my activities I WANTED TO DO TODAY because you lack courtesy, you ain't gonna like the response and if you do it again, you REALLY ain't gonna like it because you may well have to change your underpants when it is over.