I got that from a guy whose property runs along a stream I've been fishing
forever. It was never posted until a year ago, but the signs were almost
100' back from the stream, at a spot where NOBODY walks because of the dense
thorny underbrush. The trail's 10 feet from the stream, so no way I saw the
signs. The guy began the conversation as if I'd raped his daughter. Real
nasty attitude. I asked if he was the new owner of the land. He said he'd
owned it for 40 years. I told him that if it was posted, I wouldn't be on
his land. He pointed to the nearest sign, way back from the stream. I asked
if he'd finally posted because of all the litter. Of course, that's usually
the reason, and he confirmed that. I always have a small plastic bag in my
vest for litter. I pulled it out, showed him, and said "I've been coming
here for years, and I've never left as much as a one inch piece of
monofilament (vest pocket's filled with pieces), and I usually pick up other
peoples' containers as I leave". The guy shook my hand, introduced himself,
and told me to watch out for the poison ivy up the trail.