Think like a stealership
"If the pan has been replaced, how do I know the correct fluid and/or correct amount of fluid are inside? Those can clearly affect how the transmission works, warranty void!"
The thing about a lot of extended "warranties" is that they aren't warranties, per-say. They are service contracts, which are not as bulletproof as a factory warranty. Mag-Moss does not apply to service contracts, so if the dealer wanted to, they could claim a transmission pan change voids the WHOLE "extended warranty" even if you are there for something unrelated.
Even (and especially) for the MaxCare Lifetime I have...Im fairly paranoid about keeping it intact, because I bought it basically hedging on cam/lifter and/or transmission issues (very far) down the road. I could honestly fix everything else in the truck myself, but those 2 are hefty (parts, cost, labor) jobs that I would rather let the dealer do if it ever came down to it. So far, my dealer seems OK...fixed my fuel pump/level sensor unit no questions, just paid the deductible. Ive also talked to them about me changing the oil and if the lifters ever went, they said the first thing they do is pull the valve covers and can tell right away if the engine has been taken care of...they wouldn't question who did the oil changes if the engine looks clean.
The one thing that gets me is the transfer case and transmission fluids. I know there are (much) better than OEM stuff out there, but I bet if they see something different than expected color, they would make that a red flag.