With our current economy, this suggestion could possibly lower one's credit limit without any increase in the credit line. As I understand it, whenever your credit score gets run, it postentially lowers your score. Additionally, banks have been slashing credit lines, even with their clients with near-perfect credit.

http://www.bloomberg.com/apps/news?p...d=adCwmmkzFI3U
http://www.npr.org/templates/story/s...ryId=102863572

Now, as a former hotel Revenue Manager (although not with any Marriott brand), it seems that huge holds on prepaid rooms is likely to be a lazy or poorly trained Front Desk person. (At least, that was always the reason in the 4 hotels I worked.) The computer system is programmed to obtain credit for the full room/tax plus an additional percentage for incidentals. Our computers couldn't tell if the room/tax had been prepaid. So, unless the Front Desk person did an override on authorization by lowering the amount, the guest always got hit.