It is well known that people scour the internet looking for car numbers plates on cars for sale.
Then when they find a car the same as theirs they get plates made put them on THEIR car and drive THEIR car round with someone elses plates on.
So if they get done for speeding or parking fines or the London congestion charge the fine goes to the other person.
It can take weeks or months to find the "fake" car, and before they do the fake car has run up thousands of pounds of fines.