Anyone fleeing a ranked pvp match should lose twice the normal amount of points as they would have lost if they had stayed and lost the match. This means even if you fled and were on the winning team you would suffer a loss for your flee. Additionally, anyone on a team which players had fled should lose 5 less points per person who fled should their team had lost. That is to say if you are at a 4v4 table and would have lost 17 points, but three of your team mates fled your side, you would only lose 2 points while each of them would each lose 34 points.
Fleeing in pvp needs to be stopped, or at least penalized heavily.
Pvp with your friends. I'm sure they wont flee on you. :D At least I would hope so. Quick joining 4v4 matches is kinda sketchy since a lot of people make premade teams that are usually pretty good. Ask your friends for a premade team. Should stop the problem of people fleeing you get!