It's not uncommon, nor a very terrible thing, for someone to forget brackets occasionally.  Hopefully this only happens infrequently.  People flagrantly using copious OOC, whether marked or unmarked, in public channels is unacceptable for a roleplaying game, however.  Any rules to enforce roleplay should thus be designed to prevent OOC from becoming the norm, not designed to punish slight uses of it.

With that in mind, entirely precluding people from using bracketed OOC, in any channel, is the wrong way to go; it could alienate decent roleplayers who unwittingly send a bracketed OOC message and then get ostracised for it.  And sometimes you just need to convey OOC information, like "[afk, my house is on fire]." 

People who are unwilling to accept that this game focuses on roleplaying, and/or who are just here to powerlevel in a free game, are simply more suited to other games and shouldn't really be here IMHO.  It's okay for a game to focus on a limited range of playstyles when there isn't publisher and profit pressure involved.

Actually it's anti-noob.

I'm looking for information about RP guilds that roleplay heavily in all channels, preferably with the allowance for OOC comments in parentheses or such, and preferably with an edge of insanity IC.

Heh.  I updated by clicking furiously on the updater in the task bar, minimizing and unminimizing, until it was complete.  Hello carpal tunnel. =P