Well being as I foolishly left the dealer and drove a few hundred miles before deciding to research the matter, they could easily tell me to piss off. Granted there's no reason that such a short drive should wear out supposedly new fluid, but on my own, I have to way to prove I didn't do something silly to it myself. So the way I see my options:
-buy a whole new flush (or fluid change) from someone else, for $150-200 (more if I demand OEM fluid) Not much cheaper to DIY
-$25 test to prove CHEMICALLY and irrefutably that a change was not done, or was only partially done, and that no other factors contributed to the greying, then get the dealer to redo all services, under my supervision, for free, under threat of legal action
Bonus to doing the test is verifying that the radiator/transcooler is not leaking, which I could get repaired while I still have warranty. If something like that exists and caused even slight damage to the trans, I could argue to get that replaced too. Granted the warranty company won't want to suck up that expense, but once again, with the evidence in hand, they'd have no choice but to inspect it and verify the problem.
So in short, no, I don't see a $25 lab test as a waste of money. While I appreciate the "tough love" and admit I was stupid to have left in the first place, well we live and we learn. I'm going to have to deal with the situation as it stands.