I hope Mayweather will not run away around the ring because it is only an exhibition match. No need to count on punches or anything but just fight toe-to-toe. Anyway, there will be no belt at stake so he should not worry if he loses this one.
That's his bread and butter, not to be hit that's why he really hasn't taken any damage throughout his career, but majority of the boxing fans doesn't like that at all. Regarding the exhibition, why not full 12 round fight with Manny though. Pacquiao is against any similar exhibitions and I doubt that he will bite into this one. He will taint his legacy if he accepted an exhibition or fix match with Floyd.
Manny all ready stated in an interview that he is not interested in Mayweather's proposal of an exhibition match. It would be more boring than their previous March if this happens and I doubt they can make more money from this.