That's the official position. I'm pretty sure, but of course I'm not suggesting you do so, that if you pay with a prepaid credit card and call yourself Random Person you will have no problem. As I said in another thread you can also just show up and buy ticket cash at the entrance from whomever sells them, but of course you risk not getting a ticket. Depends on your concerns. I'm pretty sure if you have a better solution but such large scale event you can contribute directly.