This topic may have been beaten to death in the past. Please forgive me if so; I have not seen it or found it.
In the early to mid 1970s Cornell's Tommy Brown wrote a most excellent fact sheet on land owner liability, pointing out the differentiation in risk of being found liable depending on whether the plaintiff was uninvited, invited, or a paying customer. I see a couple of county Extension offices still lean on that in their web site postings, 'tho it appears to be out of date. (maybe?)
This paper, prepared for the Northeast Cave Conservancy in the year 2000, while not mentioning the three levels of possible liability, does seem to paint a picture of minimal risk of liability.
Here is a link to a paper published by the NYS Bar Association . . . date not stated . . . offering a more thorough examination of the problem
What is considered the norm of understanding for folks here at Forest Connect?