I dont think you could call Hughes v. Penn a fluke, Penn completely commited to the sub attempt w/ a reverse triangle/ arm bar and did not have the strength to keep the arm extended. He gassed, the injury helped however if it happens during the fight because you put yourself a vulnerable position shit happens. This GSP v. Hughes will be decided by who can enforce their game plan. If GSP can keep the fight standing he will dominate Hughes but if Hughes can get half mount or some dominant position after the 3rd round I would see it going to Hughes. Munson is a great submission fighter, however w/ Sylvia's leg size his sprawl is amazing(the only successful take down I can remember is v. Mir where he just falls into Mirs guard) I think because of the height advantage it will be the jab that makes the difference.