Hobos & derelicts make use of abandoned buildings.
So do junkies.
It might not be a good idea to meet some of these people alone, at night, in an isolated area that is seldom patrolled by the Law, when nobody knows where you are.
IMHO.
When I was 16, a buddy of mine wandered through an abandoned museum near the Astrodome. I was constructed to look like a castle and quite inviting. A private security guard, the owner, both with shotguns pointing at us, and a mean looking dog (a german sheppard, I think), were facing us when we obeyed the order to come out.
Forgot to finish, he let us go with a warning, and our parents phone number.
Yes, it is against the law to enter an abandon building. My son was arrested for it with 3 other boys.
They can be charged with trespassing, B&E (breaking and entering) and burglary. If they are minors, they may end up with a juvenile delinquent record.
ñañi, does this asylum happen to be in Menlo Park (Edison), New Jersey?
No, xvx, it happened in Pennsylvania and they were arrested for going into an old abandoned building.
Right,Cillasi. They were only 12 and 13 years old.
You meddling kids!
Astro, just shows you what is happing in the world today. Years ago the Cops would have brought you home to Mom & Dad for a good spanking. And you would never do it again.
A perfectly good Scooby aside lost… like tears in the rain. 
Those kids should have just left it alone for years and waitied until the farmer got old and came down with Alzheimers, and one day went to check on the old farmhouse, and . . .
I filmed a 16mm short at an abandoned movie theater. It was up for sale, though, so I don’t know if I did anything wrong. We didn’t steal anything obviously; we took some shots of it and left. But if it’s shown at festivals, I’m wondering about that…