So you made me look.No. GFCI compares the current moving through hot and neutral. It doesn't depend on the green ground circuit.
I’ve used a tester for years (cuz code inspectors when I was an apartment manager wouldn’t accept the ‘test’ button) and I noticed the tester “failed” without the bare. Plus they have that little notice about the ground.
And so just now I learned this:
“GFCI works fine on a 2-wire circuit, it’s just your typical tester that won’t work. The tester needs a ground to be able to simulate a leak to cause it to trip. It will still trip if there is an actual current leak or if you use the device test button which does not require a ground to work.”
Either way I guess I didnt realize the tester did differently and assumed the inspector was being picky?