That is a myth, they actually have squirrel cams. Sneaky little spies running around from tree to tree with embedded cameras mounted on their furry little bodies that transmit live transgressions back to Central Ops....
Was told of a place that was a local camp and the location of their practice range. At least that's what the old man who's family owned and still owns a good bit of land around there told me. Will have my detector soon.
There are numerous civil war sites in Georgia that are not protected by state, federal or local governments.
Even some major battles lie on private property. Of course, the probablilty of finding anything at a small skirmish, a camp site, a now developed property, is slim and none.
I recall an artillery shell was excavated at a construction site in Atlanta, more than 100 years after the battle. Needed something more than a "metal detector" to find it.
I was inventorying potable wells in the Murfreesboro Tennessee area many years ago and visited a home that must have had 20+ tennis ball-sized cannon shot laying around the porch. I was working with a Civil War relic buff at the time who was from that area and he indicated when he was growing up it wasn't rare at all to find such relics. I have no idea if GA has such places, but I suspect there are still many such places in Tennessee.
I metal detected for 12 years mostly for relics and was fortunate enough to have permission to hunt on a whole bunch of places. All of that now has gone away. And there are still 20 zillion parcels of land full of relics, but try and get permission to hunt on them. The main reason people deny permission is because others have hunted, left the area full of holes and litter. Secondly, people now realize the relics can be worth a fair deal of money. Back when I did it 30 years ago a regular "US" bucket right out of the ground was worth around $25 to $30. Now it is $100 to $150. So most land owners even though they would not detect on their land themselves, don't wish for someone else to make money off their land.
Remember about trespassing if the land is not yours, then it belongs to someone else and if you do not have written permission in your pocket once you step off the right of way onto the land you are trespassing. No sign has to be up, no filing at the courthouse needs to happen.
Another trouble is parks, school playgrounds and recreation areas. Many town prohibit detecting and even if they don't someone will call the cops and they will run you off. I got run off more than one rec. area. Why - what law? Destroying public property. No matter how careful you are to plug things out and refill even little holes and that sort of thing, some places can be picky.
To those that say they know an area they can hunt on with permission - man you need lots of areas and places you can go back to time and time again. I kept brief records for a couple of years and with relic hunting I dug on the average 137 items of trash or little value for each thing like a buckle or button or a tool that had even a small amount of value. One thing that is common between a gambler and a relic hunter is you only hear about what they have won/found, not the many more times they have lost/found very little
Back when I was detecting there was a story about a guy detecting on the Chickamauga Battle field. There is a lot of woods on that Park site and this guy painted his detector black, wore black and a black ski mask. Would get his wife to drop him off about ten at nite and come back to get him in the morning before sunrise so no parked car would draw suspicion. He even had a vinyl tablecloth he set by the area he was going to dig to put the dirt on so he could put all the dirt back in the hole so no trace would be left.
Of course he was careful not to keep going back to the same area and that sort of thing and he was successful doing this for several years. Then one night he crossed paths with a pack of stray dogs who started yapping at him just when a Ranger was passing by on the road and he was caught. They confiscated his detector, they searched his house and took all of his relics , and he was fined seems like it ended up costing him around $2000 not counting the worth of the relics and their were many and this was back in the mid 70's.