Chasing electrical gremlins - GFCI outlet puzzle

I think an analog voltmeter typically has a full scale current draw of 50 micro amperes. All the current goes through the meter movement. If it says "20 000 ohms per volt" on the meter face, that means 50 micro amps for sure.

That's more than a digital meter but still it leaves room for a misunderstanding with a high resistance short.