Pay for parking via mobile phone?

[pdv6]

http://news.bbc.co.uk/1/hi/england/2170515.stm

All very well, but how do you prove where you were/weren't a month later when the bill comes in & the thieving b@$t@rd$ have overcharged?

[Toffer]

This assumes you are somewhere that the phone works long enough to complete the transaction before cutting off ...the wonders of digital technology!