Originally Posted by Viajero Joven
Maybe I'm pessimistic--- but I always thought it was a safeguard in the event your car is broken into and stolen.
I always keep my parking ticket in my bag, etc. (as opposed to leaving it in the car) hoping that if, heaven forbid, my car isn't there when I return, the parking folks would have some special record, video, etc. of the person who drove out.
Aha! I always used to take my ticket with me, until one time I got a ride from a friend and she left the ticket in the car. "What a great idea...then you'll know right where it is when you get back!" I thought. So last time I flew, I left it in the car.
But this makes a lot of sense, and I'll be keeping my ticket from now on. Turns out my iniitial instincts were right after all!