I appreciate what you say here, but two and a bit weeks on and hardly anyone is using the Carrier prefix. It is annoying, because when visiting the iPhone forum, I don't want to see whether T-Mobile or AT&T or Deutsche Telekom are having a big sale, or have improved their contracts. I want to talk about the iPhone.
Just to illustrate my point, I've attached a screenshot from today showing only a portion of the first page. 9 out of 26 topics are about carriers. That's over a third of the discussions. The vast majority of these also don't use the prefix, making it very hard to filter them out.
I just think the idea of a Carriers sub-forum should be revisited.
I admit that i'm a pretty lazy browser.. and opening up the iPhone forum and seeing something like this makes me quickly exit said forum.
Also, I wouldn't call the moderators of this site lazy. If anything, i'd call a few of them a bit overzealous. (Don't take this too personally, because I have a very small sampling of this site -- because, you know, i'm a lazy browser)