The Ability not to offend a particular person directly put the ability ti make references to a small group that have been annoying you lately.
It's called "not saying it on the site".
I sincerely doubt an 18+ forum would in any way allow what is essentially flaming, just as people having been banned for mockingly insult others before.
Besides 18+ =/= 'You are not magically not offended by being called an [explicit with an explicit explicit].'
Of Course the ability to say this person is spamming or being offensive would still be there if the person just crossed the line.
When did it ever become okay to go "Dude, u spam"?
Either way, I doubt that would be the purpose of such a forum section. Adult matters and less strict on the pg13 rules seems fine, but making it a place where you can insult people it probably never will be.
And I agree with Dev. How the heck is someone to avoid the less-than-18-years'o'age users from appearing in the section, when you can easily change the age in your control panel?
Not to mention whether this can't be accomplished in the regular forum sections, considering we have already had a discussion on fetishes and pornography in the WEPR earlier.
It's just a matter of taking the right stance, be mature about it and possibly warn people in advance.
And get some blessings from mods.