From my most recent exchange with GMs:

As we have stated in our replies, what you are referring to is not an advertised or supported feature. It may, at our discretion, in the future be declared an exploit. Current available information indicates that this is not as it should be, until we have more information we will not be announcing anything nor taking action against those making use of this.
Our actions have been fully within the boundaries of the EVE Online reimbursement policies which are available to you on our website.
URL: http://www.eve-online.com/pnp/
If you have any further questions or concerns then please do not hesitate to contact us again.
Best regards,
Senior GM Spiral
EVE Online Customer Support Team

CCP Spiral,

So it's a bug. Why all the pussyfooting around? Why state that it's "not an advertised nor supported feature", a statement that is open to interpretation? If it's a bug, call it a damn bug and be done with it. Instead you continually leave us wondering if it's an emergent mechanic that is valid, or something that we really shouldn't be doing. It took a week, thousands of words written on the subject here and elsewhere, and no doubt dozens of petitions that your staff had to deal with, and NOW you give a half-confidence "current information indicates that this is not as it should be". Well, do you know how your game is supposed to work, or not? Do the other GMs?

I strongly suggest a memo to all your GMs informing them that this is a bug and reimbursements are valid for it, because there have been as many different answers to these questions as there have been GMs responding to petitions on it. I know that it only takes a GM 30 seconds to produce a noncommittal answer to an exploit petition, but for us it impacts the core of our gameplay. Next time, hold a damn meeting, decide on a stance, and start responding appropriately. These milquetoast responses from folks that are supposed to be authorities leave a tremendously sour taste in our mouths.

Phew. Sorry you all had to see that.

So if CCP won't say it outright, I will. Aggro extension is a bug, and if taking advantage of it isn't an exploit now, it certainly should be. I'm considering this "resolution" for my purposes, but I'm very unhappy with the way CCP has handled this. Customer service fail, CCP. Maybe the GM training program is taking an 18 month break just like development on your flagship software product?