The decision by Lufthansa and SWISS to impose significant surcharges on some flights booked through the GDSs in four European countries came as a nasty surprise to much of the industry.
The first many of them knew about it was from Lufthansa's press conference.
There are two aspects of the move that demand attention: why the airlines chose to do it without prior talks and what effects it ids likely to have on the German, Austrian and Swiss markets.
There is little doubt that Lufthansa and its fully-owned subsidiary SWISS, with most other European airlines, watched in fascinated horror as the GDSs and airlines in America fought over fees and contracts in the summer of 2006.
The episode was marked by a particularly bitter confrontation between the US's biggest carrier, American Airlines and the country's biggest GDS, Sabre.
The spectacle was repeated, though on a lesser scale, in the UK last winter when BA was in prolonged negotiations with Galileo, the UK's biggest GDS, Sabre and Amadeus over new contracts and new fees.
Deals were signed but not before much mud was slung with Sabre accusing the British airline of trying to shift its distribution costs onto the corporates.
Almost certainly Lufthansa and SWISS wanted to avoid any such scenario, hence the secrecy. But the other side of the coin is that the GDSs, let alone the agents and their corporate clients, feel greatly aggrieved.
Amadeus, the largest GDS in Germany and, ironically in the circumstances, partly owned by Lufthansa, was pointed in its reaction. "This decision was made unilaterally by Lufthansa without any prior consultation with Amadeus. We were first informed on 17 January," it said.
While the two carriers' take it or leave approach is not likely to be forgotten quickly, it is the consequences of its decision which will probably have the longer term effect on the market.
When GDSs were the only major channel through which airlines fares could be distributed, they inevitably could use their top position to charge high fees for each booking. The airlines which - again a touch of irony - founded the GDSs made clear that they regarded these fees as too high.
When the Internet arrived, enabling airlines to set up direct booking facilities with their customers, the dominant position of the GDSs was eroded. So the airlines thought they could persuade them first to reduce their fees and then to sign up for "opt-in" deals or, failing that, levy surcharges on agents for going through the GDSs.
This is what happened in America in 2006, in the UK in 2007 and now in Central Europe in 2008.
BA charged £3 per booking to agents who booked through GDSs outside its preferred channel programme. Lufthansa and SWISS are levying equally weighty fees of €4.90 and €5.
As Amadeus pointed out "Lufthansa seems to be charging more than the cost of distribution for GDSs access to its "Preferred Fares": the €4.90 fee exceeds Amadeus' average booking fee for Lufthansa flights out of Germany."
Agents of course will be left with the unenviable decision of whether to absorb the surcharge or pass it on to their corporate clients. Each way they lose, whether money or goodwill.
But there seems to be more to Lufthansa's decision. If other airlines in Europe were to follow Lufthansa's lead, like Air France KLM and Iberia, then it would indicate a major shift in power from the GDSs to the carriers.
Michel de Blust, general secretary of ECTAA/GEBTA, the associations for European agents, said the Lufthansa decision was "unfortunately the type of decision that is copied by other airlines."
But he made the point that in other industries the suppliers paid for their own distribution costs, like supermarkets taking their goods to their stores or oil companies paying tankers to deliver their product. "Why should travel be different and why are the airlines always taking hostile decisions against the distribution network?" he asked.
"What is at stake is not only a price increase but also the impartiality of the agents."
But he said there was one good thing to emerge from the Lufthansa action. "This decision is very timely because we are about to show to the European Commission and the European Parliament what the market is likely to be like once it goes ahead with the CRS Code of Conduct revised in the way the EC has proposed.
"Lufthansa has simply provided us with a wonderful example of how the revised Code would work. These are points that we shall be bring to the EC's and Parliament's notice."