It would be nice,as you say,but no player these days would dare to incur the wrath of his manager,owner,and fans by doing it. There is far too much at stake and too much money involved. Even in cricket,that supposed bastion of fair play,it is extremely rare,esp in the professional game,to see players walk even when they must know they are out. It seems it is only in golf and snooker (both individual,not team sports) that players still hold to the ideals of fair play (and that's if you can call snooker a sport and not just an overblown pastime)