How would you run an ethical MMO cash shop?

Today’s Daily Grind topic comes to us in a roundabout way from Kickstarter donor Le Entrepreneur, who asks,

Why do MMOs use cash shops they know hurt players?

There’s an easy answer to this — because money — but it’s worth exploring in more detail, I think. Cash shops in general, after all, don’t hurt players, but cash shops that exploit players’ desire to win or that tinker with lockboxes are deliberately preying on games’ weakest customers. On the one hand, it’s just business, but on the other, it makes me uncomfortable that whales — some of whom are just terrible with money, not actually wealthy — are subsidizing many of the MMOs we play.


Exploitative cash shops hurt all players in the long-run, though; sooner or later, players catch on and stop spending, and the game crumbles anyway.
Is there a way to run an ethical MMO cash shop that doesn’t feel gross to the players or the developers? How would you do it, and who does it the best?

TH