a friend of mine goes to conferences for free using all sorts of trickery. he finds out the name of guests at hotels by lying to the front desk, he get conference badges and alters them with his name and picture. he sleeps in bathroom stalls and lobby sofas and the like. i don't think he'd every hurt someone---more of the civil disobedience type. it's amazing what he can do in a "wow i'm free" kind of way.
TED probably has better access control, but I've gotten a press badge to a conference simply by filling out a web form and saying I was a "photographer from the Economist." Another conference, similar to "Foo Camp", I just went to the event site and walked in. Nobody ever asked why I didn't have a badge, etc.
My sense is that the karma police have about a ten-year backlog at this point. They're going to have to burn through the thus-far uncaught real criminals before bothering with the harmless guy who lies his way into an elite conference.
