The tl;dr: > Your boarding pass for a flight can sometimes be used to get your passport number. Don’t post your boarding pass or baggage receipt online, keep i

The tl;dr: > Your boarding pass for a flight can sometimes be used to get your passport number. Don’t post your boarding pass or baggage receipt online, keep it as secret as your passport. > How it works: The Booking Reference on the boarding pass can be used to log in to the airline’s “Manage Booking” page, which sometimes contains the passport number, depending on the airline. I saw that Tony Abbott had posted a photo of his boarding pass on Instagram, and used it to get his passport details, phone number, and internal messages between Qantas flight staff about his flight booking.