Manny Paquiao vs. Floyd Mayweather?

Looks like it will not happen.
http://www.latimes.com/sports/la-sp-pac ... 1564.story
So, what's the big deal about giving a blood sample? Think Manny has been doping?
http://www.latimes.com/sports/la-sp-pac ... 1564.story
Manny Pacquiao's promoter says fight with Floyd Mayweather Jr. is 'dead'
Bob Arum, upset that Mayweather's camp wants Pacquiao to submit to random blood testing, says he is looking for other possible opponents.
So, what's the big deal about giving a blood sample? Think Manny has been doping?