There is a vociferous debate going on in the Fl IAEI BB about this.
It is currently a tie. Some say the table rules, the GEC is a "conductor" and if it is buried between the electrodes or from the electrode to the building it has to be covered per 300.5 table. Others say article (text) 300.5 only applies to "cables and raceways".
NFPA has rejected several proposals to specifically expand the language to include the GEC so the intent seems to be that this is not what they think it says. The other side says they rejected the proposal because it would be redundant.
Why keep a fun fight like this in Florida? What say ye?