I know for a fact that the last two Ford I bought got "dealer prep," mostly becasue they made me wait while they did it. The salesman actually let me go watch them prep my F150 (including the stupid process of pumping down the tires and then refilling them with "Nitrogen" - I told them no tot bother with that, but they did it any how). On my Fiesta, I actually had to make them stop prepping the car becaue I needed to leave the dealership to make an appointment. The salesman practically had to beat the car wash guys away from the car so I could get it and go (but they did fill up the tank with gas and it was immaculately clean inside).
Ed