It's not very common, but sometimes people who check a vehicle that's parked in an unusual rural location for stranded occupants, distress or the like, "flag" it so that next person driving by knows everything is ok and there's no need to do the same.
I agree. Obviously, it seems the "Jacking with the door" was just the guy tying on the flag. If it was nefarious, I doubt the guy would announce his presence like that. There are areas during the regular hunting season, especially on public land, where I see cars/trucks parked along the side of the road all the time. It takes something unusual during those times to get me to stop and check things out. But, at night, and at a location I am not used to seeing a vehicle parked, I will stop and make sure the person/persons, do not need help. Been more than once, on my way to a deer stand in the wee hours of the morning, when I have come across a car in the ditch or stalled. Sometimes, it's just someone trying to sleep it off. One time it was a vehicle in the water and the girl was wet and cold. Since it was before the days of cell phones, and I had to give her a ride to the closest open gas station to call the cops and then give her a ride back and wait with her till the cops came, I didn't make it out to the woods that morning. If the guy was local, the
"load of hogs in the back of my truck" should have been a clue....or maybe not. Either way, it just seems to me, to be a case of a good Samaritan, making sure there wasn't a problem.
This reminds me of a time, maybe twenty-five years ago or so and I was bow-hunting public land. It was also opening day of duck season and with a good number of flowages nearby, I kinda knew the wardens would be out in force. But, even when getting out of my bow stand early, the half mile walk out, in the dark, with my climber on my back, took a considerable amount of time. Going to the back of my truck in pitch black darkness to open the topper and put the bow and climber away, I heard a rustle behind me in the ditch and caught sight of movement coming towards me. Always leery of leaving my truck parked on the road, on public land, and my construction tools vulnerable to thieves, I immediately swore and took a swing as the person approached. As he ducked, he shined a light on his hat displaying a wardens badge and announced he was not a thief, but a warden. Over his radio, I could hear his partner(a good friend of mine laughing), as he sat in his truck farther down the road. He knew my truck and thought it would be good training for the new warden in training to sit in the dark and wait for me. My friend also told me they thought maybe the amount of time it took me to get out, may have been because I was hurt or had a deer that needed the tag validated.....and yes, they were in the area because of the opening day of duck season. The new warden learned to announce himself [b[before[/b] his presence was known. It was something we talked and laughed about for many years, but at the time, I thought I was in deep smuck.