The last time I was stuck flying with them the plane wasn't even 1/3rd full. A few people, sitting near the front, were part of their ridiculous set of reward tiers. The rest of us? Packed in the back. After the attendants closed the doors, we got the go ahead to just move to sensible seats of the exact same size and amenities, but that they'd have wanted us to pay extra for.
The airline knew the flight was empty the night before, and so did everyone that went through the check in process and sees all the empty seats they tried to upsell. Is the chance for an extra fee or two beat having the old black lady next to me look at the empty middle of the plane and ask if we were in American Airlines or in the Montgomery Plane company?