Assuming BLDC motors with the ESC positioned at the 'worst case' (furthest distance) with longest power wires between the ESC and the motor, will braiding these three wires reduce the EMF that would be produced by unbraided wires? Or, would shielding these three wires work better? Is it even needed if the wired are inside a carbon fiber strut? After all, the CF is conductive and will act as a shield against EMF.
The braiding of motor wires should only be done for looks. It looks cool and that's about it. It may actually cause problems with smaller motors. I once had braided motor wires on a brushless whoop size quad and the braiding of the wires caused the motors to behave erratically at start up. Sometimes they would start spinning. After removing the braids they started up perfectly every time.
The BLDC motors we use on quadcopters are 3 phase wiring, so probably the best answer of from the electronics stackexchange Braiding 3 Phase Wires.
Twisting reduces electromagnetic effects (both radiation and reception) in two ways. Firstly if the wires are loose twisting them keeps them close together. Secondly twisting mixes up the direction of the magnetic fields so when viewed from a distance they mostly cancel.
I would expect braiding to have a similar impact electrically to twisting with the advantage that it won't come un-twisted.