Link here. Do not agree. 1. Players, as a whole, agreed to this system. 2. Players are 'penalized' only one season by taking the qualifying offer, and that with a noble goal: 2. The system incentivizes continuity - and while that may be a fail for a few in a minority of cases - as a whole it's good for the league.
Well hell, the players should fight lots of things, starting with the salary cap itself. I don't see any point in trying to defend the fairness of restricted free agency since fairness has nothing to do with it.
