...You're assuming the seller doesn't simply take your money then sell them to the next person. Or that anyone else will care to recognize any claim of exclusiv

...You're assuming the seller doesn't simply take your money then sell them to the next person. Or that anyone else will care to recognize any claim of exclusivity as a result of your purchase. Or that they're for sale at all. In point of fact, any guarantees against any of the above are typically based on a threat of violence at some level.