I think that actually refers to the various "car sharing" programs, where someone else is driving your car, which makes sense. The person driving would be covered by their own insurance. Plenty of people are driving for Lyft and Uber and I'm sure I would have heard something about it if the insurance situation was that bad.
See my links. They are working all the angles, but drivers will lose if their insurance company knows they were renting their car for hire at the time of the wreck.
