[nradov]

That would be a recipe for confusion among pilots and controllers. They rely on visual sighting of aircraft for some operations and have to maneuver in relation to each other so if the livery doesn't match the IATA code then that increases the risk of error.

[mlyle]

Here we are talking about running out of codes due to codeshares; the planes do not identify themselves this way.

But, similar reasons: mixing branding is going to cause confusion (codeshares already do this enough without injecting a “third” airline into the mix).

[petesergeant]

All the baby AirAsias have virtually identical livery with different codes (FD, QZ, Z2), doesn't seem to be an issue

[bux93]

Since their fleets are based from different home airports, the inflight meal selection is different for FD/QZ/Z2. So, it actually comes in handy for passengers; no surprises.

[CPLX]

That’s not really true. The regional carriers like Republic and so on have had a variety of different paint jobs (United Express, American Eagle) and it hasn’t been considered an issue. Not to mention the issue of random call signs like Brickyard and so on.

And regardless of that we’re talking about codeshares anyways.