It's already got a check to put the - by their name in the who list, so it shouldn't take up much more processor power doing a check for aa/aa pk only. An alternative would be, as I'm sure not all aa's want to only fight other aa's, is that this is a separate option than plan AA.
I have always thought and continue to think it's a good solution, but on the flipside, it seems to me that the more complicated the pk system becomes due to its various flaws and the fixes to them, the sillier things get. We don't need an elaborate system of accepts to have a good pk system that prevents harassment, but since harassment is an issue with pkok and pkok is here to stay, the option you mention still sounds like a good solution to me.
can non-aa's assist in the fighting? can non-aa's heal the aa's that are fighting? what do we do when a non-aa buffs their aa friend before a fight with another aa? How do we deal with things that happen between two aa's and then get taken up between two alts that are just pkok'd but not in the new super-aa structure. When s super-aa loots another super-aa, can they give that equipment away?
I don't think it's just that the immorts have dismissed this as a bad idea, but you've only got the concept, and there's a world of difference between concept and application. I, personally, am going to want to avoid anything that is going to make admin significantly more involved for a small portion of our players, so explain to me why this solves a problem. I recognize that it's 'different.' but I don't see that it solves more problems than it creates. Elaborate for me.
Please? I'm not trying to be smarmy, and I DO like the concept, but I fear it's one fraught with peril.