When content reported by a group of people acting in concert is manually reviewed (one can dream, right?) and it turns out that it didn't violate the rules on what kind of content can be posted, the group of people is actually a reporting ring, and reports by them should correspondingly be given lower weight.

These people are acting in concert to deny some other citizens what should be a basic right: the right of free speech. There are things that shouldn't be possible to be enabled by popular vote: for example it shouldn't be possible to take the life of a law abiding citizen based on how many people antipathize him. Or to silence one for that matter.

I think that voting rings should in fact be legitimate (because they show that a piece of content is popular within a certain group of people, which is exactly the purpose of upvoting functionality), while reporting rings that obstruct some individuals liberties should be actively banned.