[WARNING] is a term coined on the Kingdom Hearts Wiki IRC used to alert somebody that they just violated the rules of the channel. [WARNING]'s
are were logged on the channel's Warning Log, and several distributions of [WARNING]'s would definitely lead to a kicking or a banning, depending on the number of violations of the rules. The term is outdated, and never used seriously anymore besides for comedic effect.
Back when the IRC had rules that we were supposed to follow, violations of these rules, notably violations that were SO NOT PG, would lead to the giving of a [WARNING] to the violator. Several distributions of [WARNING]'s to an individual user would lead to a kick, eventually a ban, from the channel. [WARNING]'s were logged onto the channel's pastebin Warning Log. This term was used a lot. So much, in fact, that it became impossible to log all [WARNING]'s distributed on the channel, and the Warning Log was abandoned.
After the demise of NumberXVMoogle, people stopped taking the rules seriously and [WARNING] distributions slowly decreased. Eventually, the term disappeared from serious use completely. Its past notoriety, however, led to a memetic mutation of the term, and it is now only used for
It is unknown when or how "[WARNING]", in all caps and brackets, came about, but it was most likely done to label it as an "official" warning.
"[WARNING]" is used to warn people that what they said violates the rules of the channel, and further violations will lead to a possible kick or ban. Don't let the page title trick you, [WARNING] must be spelled as given; "Warning", even "WARNING", is not acceptable, as it doesn't count, technically, as a real, log-worthy, warning. If you say it without the brackets, the phrase is meaningless, and you will look like a total noob saying it. When giving [WARNING] to a user specifically, you must say their current IRC name first, thus pinging them, followed by a comma and [WARNING]. Arguably, if it is done any other way, it is not a valid [WARNING].
Even though many wall o' texts deny it, it is common consensus that only the admins and ops can use it. Non-ops look like posers when they say it, which generally degrades channel-goer's opinions on the user.
Below is an emulation of the usage of [WARNING].
<AFPPER> sexual bloody feces fucking hell <NumberXVMoogle> Adola, AFPPER said a curse word. The incident has been logged, and will be reported. <RandomBro213> SO NOT PG <RespectOPble> AFPPER, [WARNING].