Burning Flipside here in Texas has had a lottery system for the last few years due to not being able to exceed 2500 people on site or be under the TX mass gathering law. They make the lottery a little inconvenient (sign up in early January, mail in a money order during one week later in the month, have the MO returned if you don't get tickets). They also have a no scalping policy and regularly go after sales on Craigslist and other sources for more than face value.
no, it's just that when you exceed 2500 people, a bunch of special provisions come into play, like having to provide water, security, vending, etc. that clash with the self-reliance/gift-economy aspect of a burn.