Things are about to get complicated as Southwest goes after the more lucrative business travel segment with changes to its frequent-flier program that leave the bargain-hunting masses behind.

Southwest's new Rapid Rewards program, which goes into effect in March, features some changes that are good for everyone: no blackout dates or seat restrictions, and points that don't expire with any earning activity in a 24-month time period. But the way those points are earned, with more points given for tickets that cost more, is clearly aimed at rewarding bigger-spending travelers.

The change makes Rapid Rewards much more similar to other airlines' frequent flier programs. While the aim is to lure in less cost-conscious fliers, the danger is that Southwest is losing a feature that differentiated the airline, contributed to its image as a friendly place to fly and kept customers coming back for more than just price.

On Southwest's Facebook page, the hoi polloi don't seem to be amused by the changes, with accusations that Southwest has been deleting negative posts and comments such as:

"Big mistake!!! As a business traveler with a company on a tight budget I used Southwest because of the average low cost flights from SFO to San Diego and the perk was how fast the points earned, and the benefit of using my free flights for anywhere! Now if the ...prices are only a few dollars more to fly with someone else in bigger, nicer planes that give me more amenities! Here I come Virgin America, plus the the way you earn points on Virgin is basically the same thing SW has gone to... but with Virgin you get cooler planes."

Or this:

"SWA used to be no frills, straight forward and trustworthy. But with this new roll out instead of saying we need to revamp the program to make it ...more profitable for us, they said Hey this is a great new program that will let you earn rewards even faster. Well that's not true for most people SWA used to serve. In their efforts to become like the other airlines they are forsaking the ones that got them there in the first place."

Over in the Twitterverse, participants in the #rapidrewards conversation don't seem to be pleased either, with comments like, "@SouthwestAir and I used to be faithfully married. Now I have a mistress and her name is Delta," and "Watch out for new @southwestair#rapidrewards program - this is a definite slap in the face of saavy consumers."

Southwest itself has not addressed complaints about the new program on its Facebook page or Twitter feed beyond initial announcements about the changes to the program.

Of course, the consumers who are expressing their frustration are squeaky wheels looking for grease and certainly can't be taken to represent Southwest customers as a whole. But as more users become aware of the ramifications of the new program, more backlash should be expected. Southwest is changing something in a fundamental way that many users didn't think was broken. Ask Gap. They can tell you how that can go.

Jennifer Sokolowsky has 17 years’ experience as a lifestyle and business writer and editor in the United States and Europe. She is currently based in Seattle, WA.