How many posters in this thread have flown a Hunter and experienced the startle effect of the anti-G system running out of air? I don't know whether Andy Hill wore an anti-G suit for his displays, but I recall once pulling off a strafe run at Pembrey (around 100' agl) when the anti-G ran out of puff. You suddenly experience unexpected grey-out and for a brief moment wonder WTF has happened...
Not so in the Hawk, which had a bleed air anti-G system, as did the Gnat.
G-LOC was not briefed in my fast jet training days (last time being 1980), involving quite a few aircraft type training courses at North Luffenham, whereas grey out and black out certainly were.
This article
https://www.flightglobal.com/FlightP...20-%201585.PDF which concerns Jim Hawkins' fatal Hawk 200 accident, gives an excellent account of the effects of G-LOC. I suspect that AMTC started including G-LOC in its Ruddles appreciation courses following this accident in 1986.