How far is "Too Far" and how much has this been statistically proven. (Not Arguing I just want more info)
Not much of training has been statistically proven due to the complexity of training, and this particular fact is supported by official statements from the BB team (I don't recall whether it was in the forums; it might simply be in the rules).
If I had to guess, I'd say this you can't necessarily define too far, this feature is probably always in effect and gets particularly noticeable as players become progressively imbalanced.
"I don't know half of you half as well as I should like; and I like less than half of you half as well as you deserve."