If you want chapter and verse go to pepioo.com and look up the various threads on this
In a nutshell. MOST car parks near stations are covered by by laws (TfL give a complete list) Where by laws are in force only the DRIVER is liable and is taken to court
The alternative offered by the Private parking thieves is offering a 'contract' for parking there , In effect what they are saying is
Pay us X pounds and we will get the TOC off your back,Which i think, is a bit dodgy in law and will be the ONLY way they get paid, if it goes to court it is a 'fine' and they dont get the money, that is why they will try every trick in the book to get the RK to pay, threaten CCJ ( wrong, CCJ is only applied should you fail to pay after being convicted in court) debt collectors ( no power in law unlike baliffs)
They way to deal with these cases is
1) NEVER say who was driving, it is not sffiencient for the PPC to assume the registered keeper was the driver
2) you then play letter ping pong with the PPC until 6 months is up and the bylaw times out.
The PPC then has 6 years to bring a claim against the driver, and as they do not know who that is they are stuffed
Anyway more info on pepipoo.com
Airports are exactly the same they are covered by bylaws
HTH