Judging by the activity on the mileage run forum, it's pretty clear that the butt-in-seat rule applies to pretty much all airlines when it comes to earning EQM. People are clearly willing to spend money on MRs to get status. If you hunt and search on NW and time things right, you can get 18,000 EQM for about $800 (maybe less).

So why can't you just tell the airline look, I'll give you $800 for these flights I have picked out, you give me the EQM, and then you sell the seats again -- thereby making twice as much money? Seems it'd be more efficient for the passenger to just pay what it's worth to them for status ( like for lounge access) and more profitable to the airline, which could resell the seats!