A lot of airlines are now investing in technology to track broken married segments, hidden city, churning, etc.
They are trying to stop it for decades.. As long they work with married segments there will always be a way to cut out the leg which you don't need... DL even sent out an email that for tickets issued after 24 hours there will be no DM, because they are so confident that their robot will pick it up, still I have no problem getting V/X class whenever I want
P.S. I am not a TA, I just like to play around with a GDS.