[MrLeRoy]

No, the raves I've heard of take place with the permission of the property owner

I've heard different.

From who?

Last spring, the Chicago City Council decided "to crack down on wild rave parties[... "]. Taking a dim view of such goings-on, the city council passed an ordinance threatening to jail building owners or managers who allowed raves to be held on their property. - http://www.reason.com/0201/fe.js.sex.shtml

[Paul C. Jesup]

Whenever I heard about a rave, be it in a newpaper, on tv, or on the internet, it almost always dealt with someone illegally breaking into someone's private property, throwing a party and leaving a mess for the owners to clean-up.

But since I'm from Georgia, things might work differently in Chicago.