Now that the camping tickets are 'hangers' on the rear view mirror, there is nothing to stop you meeting the Duke rider outside and loaning the camping ticket to get her in.
If she wanted to cruise around, as long as you didn't want to use the car, the ticket could again be loaned.
But, of course, because we are British, we wouldn't dream of doing that, would we? 
hmm............... does anyone have an idea of how those barcode scanners they use work?
1) do they just scan the barcode and give a "genuine ticket" beep
or 2) are they clever and say this number was scanned in and not out "refuse entry"
I'm pretty sure its not number 2 due to the need to link to a central server for all handhelds units etc people leaving at the main gate with one guy enter with another, people not being scanned at all on exit.
but as you say Barry "because we are British, we wouldn't dream of doing that, would we"
i haven't really thought about it

Edited: last year motorbikes/ goped sometimes bikes all asked to produce camping ticket or leave it outside. Once the guys know you (e.g guy with 'tache he sometimes would wave you through) - that prob dismisses no 2 above