Carrying skis and snowboards inside your trunk equals dull edges and a snowy mess after a gnarly day of shredding pow pow. We should throw a bro in there somewhere. At any rate, as in most sports, the rule of the day is that people go inside the vehicle, gear goes outside, or else everyone gets a damp bum in the winter and a sandy one in the summer.
Thule recognized this as a problem (there's a lot of snow in Sweden, apparently) and created a package of ski and snowboard racks that solve the problem. Plus they look sorta cool.