Are you seeing this? Is it a new minimum stay requirement? Is it a Saturday night stay requirement? Can you tell me what triggered this and how to find decent AA MRs now?
My guess (and it's just a guess) would be that in the face of rising fuel costs, AA is first passing on the rising expenses to business travelers (who fly during the week and/or make same-day trips). I think business travelers are generally more brand-loyal than the Expedia-surfing occasional summer vacationer.