I don't cost share either (N-reg) but I wondered if anybody has ever done any digging on the legality of cost sharing outside the UK.
Presumably each country in Europe permits cost sharing, on its own aircraft. Cost sharing is absolutely essential to many people, who won't fly at all unless they can cost share.
However, a work-around is to fly with say 3 people and fly 3 legs and each person pays fully for his leg.