Gawdzilla Sama
TImeToSweepTheLeg
It is possible to fly two flags on one pole. Imagine the Stars and Bars above the US flag. And in Italy, right alongside the Italian and NATO flags.
In the sail navy that was a foot-on-neck move. A captured warship would have the victor's flag above the original.
And I haven't seen that set-up you mentioned in an official setting. Could be from lack of experience, of course.