Has to do with not only supply and demand.... but also convinience.

You are paying for that extra ease of just walking in and getting a car, with out any prior notice to us.... where as the person that booked ahead of time so we could try to prepare is going to get that little bit better rate.

Just think about it this way....
If you want that discounted rate.... call or go online and book it... then walk in the door... Granted you still may not get that car or the rate because you just made the reservation... but at least you have a fighting chance.

Yes, you come in off the street.... your not just a walk-in.... but a dead man walking.... bring a helmet because you are about to get knocked over the head for being an idiot and not making a reservation!!!!