I always try to ask permission before entering private land, especially if it is obvious where one should ask permission.
I have never been refused when having asked.
Ironically, the only bother I have had online is from a place where permission was given freely on a sign to visit a location; but because I had taken, and posted a photo of the monument without seeking the permission of the landowner to photograph it, I received a rather tense e-mail. The sign adjacent parking for the monument never said anything about seeking permission to photograph the monument.
If I ever have any comeback on locations I have visited without successfully gaining permission first, then I will take action to propitiate anyone feeling aggrieved. I like a peaceful life, and as far as it depends on me, like to keep it so as much as possible.
...........
Anyway, the point of my posting this thread is to aid (hopefully) further interpretation, understanding, and discussion of the monument - though I agree access and permission are important aspects thereof!
:o)
cheers
Tim