Under the table deals

[csnmf]

I read a thread on 2+2 today regarding under the table deals and someone suggested that the larger rakers all tend to go with the under the table deals and the ones that sign up with the larger affiliates are more polarised to the ones that can win the rake races and very small rakers.

Which got me wondering how prevalent are under the table deals and what percentage of players are on them? I guess the players on them are definately high rakers than average. The larger affiliates that advertise on 2+2, do they actually get that many sign ups on there when they have to specifically compete with these people pm'ing their deals to players requesting offers.