[ I have not been able to verify/debunk the belief that diet soda is shipped under constant refrigeration, but to be safe I would avoid drinking aspartame-sweetened beverages that have been stored above 80F for any significant period of time, or eating aspartame-sweetened foods that have undergone significant cooking]

this quote from "enkidu" (whoever he/she may be and...credentials?) on your "everything2" link mentions the 80F temperature, to which I refer you to my previous post mentioning human body temperature....not to mention that a lot of people keep cases of pop in their garages unrefrigerated for long periods before they put them in their fridge.
Ted....you're a Master Debater (nudge wink)
I am glad you haven't had any problems from drinking the stuff (so far) Of course I wouldn't wish those things on anyone.