Oh good point, didn't think about people getting hosed by booking lowest fare from a 3rd party and not knowing about the catches and then making DL think it is really popular.
I looked at the fare rules and it doesn't say anything regarding lower/restricted mileage/MQM earning. The purchase page also shows full MQM for the flight, although we all know how that is not accurate.
EDIT:
Other thing... is a $12 savings really worth it to buy this fare for no seat assignment and no changes?