Riddle me this....

How would you get absolute polarity if  some instruments were recorded in phase and some out of phase on the same song, I wouldn't doubt if this happens when recording at multiple recording studios.

In the analogue domain it‘d have to be mechanical and thereby more accident prone, I guess…Where polarity is messed up during recording, there‘ll be a change in degrees with in most cases one setting preferable. Since the advent of hi-res audio, polarity consistency seems to have moved into focus for recording engineers.

Have vocalists and instrumentalists also learned to record in phase with each other.? My point is if one prefers one phase vs it’s opposite it’s possibly because one is focusing on one aspect of the performance, eg, the vocalist in an ensemble.

The answer to my rhetorical question is there is no difference between switching phase 180 degrees in balanced analog mode vs digitally. Except in the latter case the signal has to be reconverted to analog after phase is altered.

I’ve noticed that when my wife and I are outta phase, our voices get louder.

Exactly.  Jobim said it best in the English lyrics to Desafinado.