Bought a roof rack at the insistence of my gf so we could put the bikes on top and have more room inside the car for bags...
Brand new car, what do you think happened? The front quick release broke and dumped my bike on the roof/side of the car (back wheel was still attached with a strap)...
$$$ later for repairs, both bikes *always* get both wheels off and go inside the car: one in the trunk, and one in the back seat. This is in a coupe btw - everyone at group rides is always amazed that I can fit both bikes inside... and they'll never go outside ever again

The bikes are always clean that way, and I never have to deal with the noise of having them on the roof... and the gf had to learn to bring less bags on weekend trips