As others have pointed out, it really will depend on the format of the Exchange. Depending on whether it's an auction system or just store system, merchants may or may not still have the ability to create and capitalize upon price diversity. The one thing I hope they include is a filter/search -- the bank alone has been needing one since ever; imagine tens of thousands of people's items all at once #-o
Yup, certain autoes have it built into them that they look for the red dots on the map, within a certain distance of the resource only, so this trick may not work all the time...fun to get those cheap autoers though.