They’re scanned by the sorting equipment. When a stamp is issued with a particular number that number can then be used exactly once, at least in theory.
They already had a perfectly good method for preventing stamps from being used more than once which was to stamp them. But sometimes they fail to do that too.
They’re scanned by the sorting equipment. When a stamp is issued with a particular number that number can then be used exactly once, at least in theory.
They already had a perfectly good method for preventing stamps from being used more than once which was to stamp them. But sometimes they fail to do that too.