My Dutch law teacher explained it to me this way: "If you are in an airplane, with your bike, then parachute down to a highway and get hit by a car. The car might have a chance to not be liable, but probably still will be."

The reasoning behind this is, whatever accident happens, one of the two people involved is protected by a ton of glass and steel, one is out in the open. The one that is protected inherently has to bear more responsibility.