What should the criteria for opponent selection of the #1 p4p fighters be ?

Do you guys think there should be some sort of criteria the 1 p4p fighters should have to abide by if they want to keep their title as 1 p4p. For example do you think it demonstrates someone is the 1 p4p if they choose to fight opponents that have recently lost and in a one sided fashion? If the opponent was already beaten by a lesser fighter, and recently, what chance would he have against the number 1 p4p fighter.

There should be some sort of criteria for opponent selection you have to abide by once you reach the number one spot, else you should lose it. It would prevent the 1 p4p from choosing fights that offer really no challenge and/or demonstration of their skills. I dislike the fact the boxers lower on the list that take multiple tough and challenging fights while winning can never take 1 spot because the #1 once earned it and his stuck on top, but is not maintaining that same level of competition that got him there.