It is always wise to be cautious when dealing with unfamiliar things, I agree.
I have been in and out of a few of them. Most seem harmless. There are some, naturally, that I would be wary of as well. And I do not suspect I have seen everything there is to see. However, the one I intend to go into is one of the more innocuous ones. There does not appear to be any human or animal life present at all. But the fauna is fascinating.