My FIL and I used to quail hunt all the time from the late 70's until just the last few years in NE Missouri. He is the kind of guy that knows everyone - or so it seams. We literally had thousands upon thousands of acres to hunt. Hardly would ever see a no trespassing sign. I would always ask him if we had permission to hunt whatever ground we happened to be on. His standard response was "well I asked him twenty years ago". Personally I think it was more - it is not posted - must be ok to hunt.
Missouri passed the purple paint law. Seemed like overnight, purple paint sprang up everywhere. FIL got to thinking he better start doing a bit more asking, instead of violating a posted mark. Quite a few people told FIL - no, for a variety of reasons. "The quail population was way down" (which was true - still is), "have a grandson who like to bird hunt", but he also heard that the "deer hunters was the reason the land got posted for". We heard several stories of cattle being mistaken for deer. Large bore holes in equipment left in the field. Gates left open, etc.
FIL has gotten so he can't hardly hunt, and you have to walk all day with a great dog and maybe see 2 coveys. His dog power - is nil, so we haven't went bird hunting for several years.
But I sure do miss those days of hunting. We might cross several landowners on a hunt, but we were never around the house or barns or equipment. I remember several times we found fence down or the cattle out - and the hunt got scrubbed to help the landowner get his cattle in, etc.
Sorry, kinda rambled on - reminiscing a bit. The New Hampshire posts made me think about the way it used to be around here. I guess my main distinction would be - if it is vacant ground - no cattle, I probably wouldn't care if others used it. But I sure wouldn't want anyone up around my buildings, equipment or other property.