Anyone that claims that the market wards can't be manipulated is being delusional, all it takes is enough money and the knowhow. Believe me RMT aren't the only ones that will be manipulating the MW and/or AH, there is no way around that.

The market wards are not even being used as intended (no one rents stalls). It was a cool idea to let the players have their own store fronts, but an impractical one. When and if this game gets more players there is no way the market wards will be able to handle all those retainers, whether they are renting stalls or not.