How do stapled old and new passports work ?
I havent seen one of these in a long time. The last one I saw was affixed together with grommets, a red ribbon, and a diplomatic seal. This is done when the old passport is expired or filled up, but still contains a valid visa that must be preserved. Passport holders should never fix two passports together themselves. If they do, they risk having their passport invalidated or even siezed for tampering. It should only be done by a consular officer of the country which issued the passports.