For New Zealand in particular, the flags that are used through history are wildly inaccurate. It's missing the initial flag used before the Union Jack was officially adopted. And the signalling flag that is on there between 1907-1947 was never an official flag and was only kind of used between 1899-1902 before the current flag (Union Jack in the corner with the red Southern Cross stars on a blue background) was adopted in 1902.
