Stansted Airport Parking - Security Measure or Intrusion of Privacy?

[Desmo]

I have to regularly pick up my old man from Stansted airport when he returns from Ireland. At Stansted, they've put in new toll barriers into and out of the car parks. Now I noticed for the first time the other night that it actually reads your numberplate on entry and prints it onto the parking ticket

Now I'd like to know what they do with this information. Can it be used for security purposes? I can't imagine many terrorists turning up in their own cars

Or is it yet another invasion of our privacy? Are they going to keep tabs on me to see how often I visit the airport?