There won't be any excuses if Floyd loses. Everyone will just use the opportunity to say that Floyd was overrated, didn't fight anyone, no Ray Robinson, etc.

The excuses will be if Shane loses because no one who hates Floyd wants to believe that he'll beat anyone unless they are at some sort of disadvantage. Shane however if he beats Floyd there will be no excuses, just every hater coming out of the woodwork to bash Mayweather and post pictures of him losing.