It had to happen, didn’t it? Southwest Rapid Rewards has announced that its “bonus credit for online booking” promotion, originally slated to end on Dec. 31, has been extended to April 1, 2005 (No fooling!).

Southwest watchers are pleased, but not terribly surprised, by the move. After all, the original offer of double credit for online booking would have made Lazarus proud by the way it kept coming back, just when it looked dead.

Of course, it did eventually pass away, once Southwest determined that customer usage of the Web site had reached acceptable levels.

But the savings realized by pushing customers to the Web are apparently too lucrative to resist, and Southwest will continue to offer an inticement.

The one-credit-per-roundtrip booking offer essentially allows members to earn three credits for each roundtrip, making a free flight (at 16 credits) available after just over five roundtrips. (One-way flyers earn half a credit.)

And unless you’ve been firmly ensconced under a large boulder for the past few years, you know that Rapid Rewards awards are free of both blackout dates and capacity controls.