And as one final note, never forget that you are trespassing at your own risk, which means don’t whine if you get hurt. Only losers file suit against property owners for not having good enough locks to keep out clumsy, ill-prepared explorers. Seek medical attention as needed, and seek it promptly; but don't pretend that any personal damage is anyone's fault but your own. Remember this as the cardinal rule of trespassing, and have a good – and safe – time out in the concrete wilds.

* In many places, if a male cop is really suspicious and wants to search a woman thoroughly without fear of a sexual harassment complaint, he is forced to call in a female cop. I've been nabbed by the police about half a dozen times for trespassing -- in several states -- but never once has the officer bothered to do this. It's much easier for him to just turn you loose, provided you aren't up to any obvious badness.