From how many fights should Ali have been DQ'ed for holding?

[AdamGB]

You're assuming that he wouldn't have done something different if he was being penalised for it.

[jahmez]

That's true but I guess we'll never know... I've got a dvd of Ali-Frazier 2 where Ferdie Pacheco is commentating in hindsight and he mentions that the holding and applying of weight on the back of Joe's neck was something they worked on over and over in training. Surely Frazier's camp would have brought it up but it's funny how certain fighters consistently get away with things. Awestruck, pressure from promoters/teams and/or kickbacks? Has there been a case where its been proven that a big name name fighter has colluded with a ref?