These are different situations. Mayweather does not want to lose his precious zero so this is a major reason to approach Paquiao with caution. Vladimir, on the other hand, really wants the fight with Haye and is confident he will win. The fight is still on the table for July. Even Haye himself can not expect Chisora to be any more than a speed bump on the road to the fight everyone wants to see. And if Chisora gets lucky somehow, then Haye will be able to stage a big money British superfight at Wembley. What's wrong with that?