USAirways implemented the Saturday night stay this year along with a bunch of other changes. Personally I don't care since if I make any award reservations it will be over Saturday night and like the other changes (segments for status, etc) so I did not complain. Apparently neither did enough other people because the change has stuck.

UPDATE

I wrote CO customer service, and here is a part of the reply:

Dear Mr. ****** :

Thank you for writing to the OnePass Service Center. We always appreciate feedback from our customers.

Currently, the Saturday night stay policy is currently under review. If a change is made, it will probably will be done within the next few months.

Thank you again for writing to us. We look forward to welcoming you aboard another Continental flight in the near future.

So as you can see, we CAN make a difference on this. Our combined input could make the change a reality.

So START WRITING!!!

This is hardly a concern of mine since I don't use miles for coach rewards. And shouldn't this be in the CO thread?

DL Doesn't require a Saturday night stay and is just one of many reasons why I fly with them.

The recent policy only underscores the need to write to these programs about any concerns we may have. Without the complaints, yes COMPLAINTS, of their members (especially elite memebrs), the airlines will contiue to shaft their frequent-flir memebrs.

Think of the "rules" as "guidelines." Saturday night stay rule? Just show up at the gate for the flight you want to take, before the Saturday night. I would bet you they will just let you on the flight. Especially with a free award. If they ask you any questions, just say you have no idea about the rule. And again, don't make the mistake of calling res and asking them to make the change. They often will document your pnr (passenger name record in computer) to say they have advised you you can't do what you asked. Then your "I've never heard of that rule," will not work at the airport. They will say "But Mr. Jones, it says right in the record, you were advised you had to stay a Saturday night...I'm very sorry but you will have to follow the rules." Before you just head for the airport, be sure to check loads on flights of interest. Good luck, and remember the rules are just suggestions.

flyer18- I hope you'll forgive my skepticism here!!! It's just not my idea of how to start out on a trip- business or pleasure!!!

Vulcan's right-UA tried to impose a Sat night stay on domestic awards a few years back. But they rescinded that, maybe before it went into effect.
I never fly CO because it's impossible to use their program for oevrseas Bus1st awards. And someone said they have a 60 day clearing of upgrades for overseas-their policy says 30 days.
As for Flyer18s suggestion of acting dumb at the gate and hoping they waive the rule, well that would certainly fit with the incredible behavior I've seen at boarding gates.