I recently finished a 20 segment journey with these BP like tickets issued in CMB. Quite an impressive wad of cardboard.
When checking in for each AA flight, the AAgent took the relevent ticket out and stapled the AA BP for the flight to it. These tickets and BPs were all the same size, shape and type of card.
When boarding, each ticket was removed from the BP and taken away. The BP was then scanned as normal.