No surprises that Lufthansa's announcement in early-June that it would be imposing a Euro 16 levy on bookings made via GDSs has turned into one of the big issues of the year.
The move has been labelled "brave", "stupid", "about time", and even had one senior executive privately predicting the person who came up with the idea would eventually be "sent to the gulag of the cargo or catering division".
Writing in Tnooz, the airline's regional director for the UK, Ireland and Iceland, Christian Schindler, said the "only losers will be those who insist on stagnation and sticking to the status quo", in an article arguing that the industry "must accept freedom in distribution".
Until recently, concerns have been made mostly from the theoretical or strategic side of the argument.
However, US-based lobbying group, the Business Travel Coalition, which is behind a movement called AirChannelChoice, a bid to raise wider awareness of Lufthansa Group's decision and stop the September introduction of the GDS tax, argues there are also legal considerations.
Although the AirChannelChoice membership list has yet to attract official support from the very organisations it is siding with (Sabre, Travelport and Amadeus), it packs a reasonably powerful punch in terms of coverage in both the mainstream and trade media.
In a note to members on July 2, BTC head Kevin Mitchell argued that the Euro 16 surcharge coming into effect on September 1 2015 could be derailed by regulators.
He wrote:

"...[levy] represents a possible abuse of its dominant market position and should be investigated by Germany's competition authority, the Bundeskartellamt, the European Commission's DG COMP and the US Department of Justice."
To date, none of the regulatory bodies listed above have given any indication that the move will trigger some form of investigation.
But Lufthansa, in a statement to Tnooz, has once again reacted strongly to any suggestion that its decision to impose the charge is unfair and infringing on any laws.
An official says:

"The introduction of the DCC (Distribution Cost Charge) is fully compliant with all legal requirements and had of course been checked carefully in advance of the announcement."
Lufthansa's Schindler spoke this week of how carefully the airline had planned the move.
In a briefing in London he said the carrier needed "to respect time-frames and clauses everywhere", and talk to all relevant authorities to gain approval.
Schindler says Lufthansa, in deciding the Euro 16 charge, took the overall cost worldwide of all tickets and fares booked via GDS and compared it to the 3o% not booked via the distribution giants. It then claims to have had an external auditor verify the data.
It seems highly unlikely that Lufthansa did not check - and double check - with its team of lawyers beforehand, but, as Google has found out on numerous occasions (not least with its $700 million deal to buy ITA Software, which was forced to wait for ten months to close the deal), regulators can soon find their phones buzzing angrily when lobbying groups get the bit between their teeth.
Meanwhile, at the briefing, Schindler also suggested much of the initial emotional reaction was now "fading away."
He added that the industry "has taken it up" and that there has also been interesting reaction from outside such as from financial analysts who have welcomed the initiative in terms of breaking the "oligopoly of the GDSs."
Schindler also said British Airways was "following in Lufthansa's footsteps" with the opening up of its APIs to encourage developers to find new ways of searching and shopping for tickets.
BA's move is part of the wider industry development of an NDC standard, led by global airline organisation, IATA.
Questioned on whether Lufthansa could go through with the charge on its own, Schindler thought it could but predicted a "rocky road".
NB: Additional reporting by Linda Fox.