Well, exclusivity, in the way that I understand it, usually entails a contract for a specified amount of time. It doesn't mean much if an item (I don't care what item or where) is advertised as exclusive at some location only and yet the next day it can be purchased somewhere else. I'd certainly hate to buy a numbered print (1 of 500) only to find the artist decided to raise it to a 1,000 because it sold so well. Not entirely the same but similar.