Why is car reg. no. reqd. when booking site?

BlueFoxFan
BlueFoxFan Forum Participant Posts: 4
edited June 2012 in UK Campsites & Touring #1

It's a silly little query I know, but why do the Club require my car registration number when I make a booking for a Club site?  

Of what use is that information?  Would I really be refused admission if I turned up with a different towcar!?