That's interesting, a few years ago basically the same thing happened to us at a local Quaker Steak.

Went to pull in the show car side of the parking lot and some young guy stopped me, and said the restraurant parking was in back. I gave him a blank look, and said I was there for the car show.
He said it was for classics , sports, and special interest cars.
I motioned to all the NEW Mustangs, Vettes, BMW's. and Camaros parked just inside the entrance, and gave him a questionable look, and the guy just shrugged his shoulders and let us in.
I guess he thought I was driving a Chrysler "K" car.