I may be looking at this rather simplistically, but if someone attempts to book more than 2 rooms using AAA rate & Marriott allows it (ie, limit of 2 doesn't show up anywhere in rate rules etc & the system accepts the reservations), I think the person making the reservation (and in aaupgrade's case is paying for all the rooms), I think it's reasonable to assume it's a valid reservation & the rate would be honored.
BTW - until socrates posted the AAA limits I had no idea there was a limit of 2 rooms. Isn't stated anywhere on the AAA card & if the rate rules don't show it, who would know? The general population doesn't check FT Marriott forum & have access to socrates or chris.
Cheers.