Let's take it a step further.
Let's say that at a particular dealer, for some bizarre reason, a minor without a license is allowed to drive a $20K USD new car.
Let's say the minor goes online and tells about his test drive.
Although some say there is no such thing as bad publicity, I'd say there is, and this would be an example. I'd hesitate to buy there or recommend the dealer. Even if the kids in the cars don't hit me or anything else, if they don't buy those cars someone else will. I don't want to be the someone.
I also can't see how the practice would in any way... lower operating costs. I have a suspicion about who ends up paying for operating costs.