Well, when I was running balanced power in the studio many years ago, the principle that we use here for that is to have a balancing transformer divide the "hot" leg into two legs of half-voltage with inverse phases. The equipment doesn't mind (in nearly all cases...but I know there's a few devices that don't like this) as a rule, and by doing that inversion, you wipe all of the noise that might be lurking on the AC thanks to phase cancellation. Also, the transformer helps to provide a more solid ground because there's no "neutral" for AC to sneak back onto in situations like this.
As for star grounds...they're not exactly THE mains ground line, which is what your codes refer to. Instead, this is more of a "noise ground"...it helps to kill stray induced garbage that's creeping around rackrails, gear chassis, etc. by creating a "universal ground plane" for the audio so that crud goes right to a single groundpoint that's designed to handle that garbage...this is usually a groundpoint on the mixer, which my Topaz 24 and FIVE both have. Years ago, I also had a Faraday shield under the floor of the studio that also connected to the mixer ground to catch e-smog creeping up from lower floors, and that was a very effective countermeasure at that time.