Towing Issues: special event parking/towing, tailgates, local restaurant

Question
I ate at a local restaurant downtown during a hometown football game.  I left my car parked while I walked down to various tailgates and came back 3 hours later to find my car...well, not there.
The sign in front of my car said "No Special Event Parking. Violators will be ticketed $40"
Even if it was assumed that I was "special event" parking, they didn't ticket me, the restaurant towed me. Which cost me over $100 and I was 30 minutes late to work because of it.
Is this legal?

Answer
Oh I can be so sarcastic here about this...

But it does sound like it was legal.. Ticket or not they do still have the rights to have vehicles removed from the property. I know that in some areas (I am guessing this is a college town or pro team area) that the parking lots are rented out to parking outfits who pay for the right to use the lot and also allow customer parking of the business. But this sounds like it is close to the station and has a great problem with the parking...   

now as the fee that is cheap from some that I have hear for towing, and sorry it made you late for work.