I saw a lot of strange stuff in the computer biz but I was a IAEI 2a, 2b, 2c at the same time that I was doing installation planning at IBM so I did try to be sure everything was compliant.
Even then the "official" description of the IG circuit had it landing on the ground electrode system of the service, usually in the service disconnect enclosure on the main grounding bus where the MBJ was.
I may still have the IBM physical planning manual around here somewhere.
You could always get a fight started with a "noise" guy about whether building steel was really a grounding electrode.
Occasionally I did find a guy who wanted a separate ground rod. I could usually make that idea go away using a current probe on a scope.
