Originally Posted by B747-437B

With all due respect to everyone posting on this thread, please don't assume the airlines are made up of idiots. Interlineability of YQs has been an issue at IATA level for multiple years now and resolution 852 was specifically introduced to counter the practise of IET on third party carriers. This was not as much to prevent "fuel dumps" at consumer level but rather initiated from BSP level because of an increase in "bustouts" where third party exposure was heavy.

A change to processes costs a lot of resource in time and money, especially when it comes to defining industry standards on a scale that IATA usually does. IATA had lead times of almost a decade to implement 100% IET and even something as relatively minor as EMD rollout has been planned as a 5 year project. Realigning something as fundamental as MITA (which despite the preponderance of modern ATI alliances still accounts for >90% of interline agreements) requires a lot of work and assent from almost 300 carriers!

Products such as IDEC have become widespread and integrated into modern generation revenue accounting software, allowing these flags to be immediately detected. However, so long as the potential revenue loss from a "loophole" was less than the costs of reprogramming / realigning a system, it made more sense to simply monitor it or counter it with a stopgap measure. Something as simple as implementing interlineability caveats or plating restrictions onto fare filings may achieve short term results, but when stopgap measures are combined in isolation, the combination can be quite deadly when loopholes align.

There are still more than a handful of ways to obtain preferential pricing on itineraries, some of which have never come close to being posted on Flyertalk. There always will be if you understand how the system logic and algorithms work (this is true for any automated process). Blaming some blogger who doesn't even understand the logic behind the great trick he was proclaiming is pointless. $h1t happens. Move on and discover the next great trick. Those with formal training and experience in this area have probably seen it before.

Note : The above represents my personal opinion, but is written with the benefit of my experience as a carrier representative to IATA and an interline manager who deals with this kind of issue every day.