It's not because he is scared to lose to Pacman.
It's because he knows he himself will fail the test that he imposed on Pacquiao. http://www.queensberry-rules.com/2012-a ... ddles.html
That's why he would rather be humiliated about not fighting Pacquiao than be questioned about all his unbeaten records.
So about that rumor...
What we know about it from this article is that on May 20, someone "with extensive knowledge in the area of drug testing" told Gabriel Montoya that he "believed" Mayweather had tested positive three times with his "A" samples, but got an "inadvertent use" waiver from USADA that made it so there were no follow-up tests. At least we know something about the source, but I'd feel more confident in the rumor if we knew from the article that this person had information about Mayweather's tests specifically, and knew rather than believed. It'd be nice if we knew whether this person had an axe to grind against Mayweather, and whether there was another person confirming hard information. The rumor "filtered through the drug-testing community," Hauser writes, and other writers have said pubicly
that they'd heard the same rumor. Top Rank's Bob Arum has referred to inadvertent use waivers but only that he'd "heard" of them. It's not clear to me whether these people heard it it independent of what came later in the form of a published letter from GBP, once Montoya began asking about it."
i dont usually like writers who writes with such style.