Hi Nowfree
I dont know how it would work but I know that at least one of the conventions on the SE coast uses NCP car parks which during use by the dubs are still open and used by the general public.
I would assume that you would have to get permission from the car operators/owners/council.
If it went ahead I dont see how the JW bouncers could go and remove fliers from cars that could belong to anyone especially as they dont hire the car park per se, but just have a number of tickets allocated in several car parks throughout the area.
Maybe others would know more about this.
Anglise