I doubt the car would be seized under those circumstances, as it would penalise the owner, which seems a little unfair as they've handed their car to the company in good faith.
That said, I'm not sure what would happen if the car was stopped miles away from the car park, say on a motorway...
Not the first time this has gone on.
Happened at least once when I worked up there. Company was offering meet & greet parking services, collecting the cars off holidaymakers, then going and parking them all around some council estate in Horley. Most of the time, customers are absolutely none...