Either way we sometimes have to transport our bikes and with that comes certain risks. I damaged my rear wheel on my bike and had it mounted on a standard rear rack, not the hitch type like the one I have now, and the bouncing of the whole thing going down the highway for some reason bent the wheel pretty good. I never had that happen before, but after that I got the hitch job. A lot of times I just put the bike in a back seat by removing the front wheel and slide the bike in then put the front wheel in; but times where I either will have passengers or more then one bike then on the rack it goes.When my bike was on a roof rack, my seatpost got bent at McDonalds drive-thru, but the driver felt bad and bought me a new seatpost
Once I forgot to tighten the fork mount and my bike fell over when I took a turn. I heard noise, turned my head to the left and saw my bike hanging there against the window. The drop out got bent almost 90º, but I hammered it back into shape.
When my bike was on a rear rack, it was totaled when rear ended by a driver in a stolen car fleeing the police. The car was totaled too. My insurance paid for the car, bike and bike rack. Coincidentally, my car was worth the same amount as your friend's bicycle!