I can see a balance. For example, I want to test drive a Trend just to see how it handles on Texas roads and the wind gusts from the semis on I-35 and TX Highway 45 with the 18 wheelers hitting triple digits. However, I can completely understand a dealer reluctant to let anyone off the street drive an expensive rig that even if insurance did pay for damage, it would be hard to sell. There is a Beavis & Butthead episode that is about this topic. I don't mind the salesperson coming along, because what I'm looking for is if I can one one-hand the steering wheel versus white-knuckling it, and that isn't exactly Fast & Furious driving.
Not sure what to do in this case, as I understand both sides of this issue. Maybe offer to insure it completely for a day on one's own insurance?