I have seen this happen on several subjects, but as it has been over a year since I actively participated and followed Wikipedia internals, I cannot immediately give you a particular example.
My observation of this abuse of policy has been as a bystander by the way. I've never actively edited any articles on these subjects.
Typical subjects where there most certainly are well organized and ideologically motivated editorial cliques include US foreign policy, anything to do with Israel, Turkey and its history, anything relating to Islam etc.
Abuse of the notability policy is just one, but very effective, tool for censoring and controlling the content though.
