Can you elaborate further please so we're all clear as to exactly what you mean, Terry?
I'd be surprised if any owner of a car park or paved private land would be even faintly dim enough or interested in allowing people to do that, particularly for free. If they allowed it, they'd open themselves up to huge amounts of possible liability claims if someone was injured or killed, or if vehicles were damaged. Disclaimers would be next to useless for the property owner in such circumstances, and the cost of insurance would be astronomical.
By comparison, paying £25-£30 quid to do it in a safe, fun and organised fashion is a complete no-brainer in my books. That's the cost of going to a movie (and probably being disappointed), a mediocre meal for two at a less-than-posh pub, or 1/3 of a tank of fuel in my tin top.
If you do manage to find someone with a car park daft enough to allow people to do that, give me his details - I've got some scrap green copper on an island off New York for sale.