Seems bellows technique is something that tends to be largely down to the individual, away from the "finer" performances referred to by Paul.
In recent years I have become something of a You Tube "addict" with regard to accordion music, and it seems obvious that some players will use certain bellows and other techniques for "show", whether it's considered right or wrong.
I'm conscious of the fact that one of the things which keeps the accordion alive in subsequent generations is classical music, something I was not aware of until I joined the forum. In an ideal world we should maybe all have been "classically trained", to use the Scottish terminology for such players, who are typically held in higher esteem than those who have learned by other methods, or indeed who have taught themselves to play.
However, the accordion by its very nature is probably better known, especially outside of Europe, for its use in the less "finer" performances seen on such media as You Tube, and in my own experience that is the type of footage which tends to grab my attention.
For me, it is the sound that is coming out of the instrument, and the ambience created that is the attraction. Even the odd fluffed note or missed chord is allowable (to my ears) just so long as the main performance creates a feeling of well being.
I have always had the greatest of respect for players of any type of classical music on any instrument, but being ignorant of all its subtleties and nuances, as well as being musically illiterate, I often struggle to interpret what a player or an orchestra is trying to convey to the listener.
Conversely, I can listen to an accordionist with no formal training, playing some virtually unknown folk style on a battered old instrument with bass and treble buttons/keys missing, and appreciate what they are doing without worrying about what if any musical "rules" are being broken in the process.
I'm old enough to remember when good "bellows technique" was useful to be able to light a coal fire quicker, and the consequent bellows instruction given to me by my late father is the only tuition I've had in the matter.
I love the accordion, the same as everybody else on here, whether it is played by people with no shoulder straps, one shoulder strap, or even if the player uses the instrument to rest a lit cigar or pipe on it while playing.
I sometimes hate being different, but that's just the way I am.