One can't really blame NW for this. When people use creative routings to pile a ton of miles for low fares on another airline, something had to be done. For example, DCA-MEM-MSY would earn you about 1262 miles each way on NW. However on CO, one could do, DCA-EWR-IAH-MSY and earn 2400 miles. With 50% EQMS, you will still get 1200 miles. So all it does is reduces the value of MR to you. The revenue goes to the airline operating the flight, regardless of the code or who sold the ticket. I think, what NW is saying is that it will tolerate creative routings as long as it gets the revenue.