Allow me to end your suffering..
Actually, it's from the Roman, Cicero, who amongst other things was a lawyer, in modern terms. What he was saying is that if there's a law saying X is prohibited on Sundays, it shows that X is NOT prohibited on any other day. In context it makes perfect sense.
It's not archaic in that the meaning of the word 'prove' still means to test the validity or truth of something by evidence or argument. Although we primarily use it today in the sense of testing something to show it is true, it is still also used in the sense of testing whether or not it is true, in, for example, proof testing establishments (in engineering) and degrees proof (of alcohol).
Consider that 'the exception that proves [i.e. tests] the rule' is about stress-testing the rule.
My alibi proves I didn't commit the crime, your honour.
p.s. Not to mention 'proof reading' - the act of finding and correcting mistakes in texts.
He sounds like a bit of a bore. Bet he sat on his own at parties.
Well, me. Don't need them. But no problem with people that do.
And if a truck driver parked on the pier is using a GPS jammer to fake driving hours? Or there's sunspot activity messing the signal up? Or there's a naval exercise in the vicinity and they're jamming GPS? In any of those cases, all your GPS systems will be so many bricks! The latter is fairly common in parts of the UK (the West Coast of Scotland especially). I don't know the range of GPS jamming units, but given that the signal is incredibly weak, it doesn't take a lot to mess it up. And that's not to mention the outside chance of a major solar flare frying the satellites and at best causing an outage of days if not longer.
Poser, then.
Some people prefer the satisfaction of using their own skills and brains to navigate, with a few basic tools and methods.
Reminds me of a fishing skipper I met in the 70's when training as a hydrographic surveyor. Our research organisation chartered his vessel. The difference is that he knew the limitaions of his navigation ability. He pointed to the Decca receiver - the big one with three dials giving the lane readings and a fourth with the spider lane ident.
I take it you have not looked at the current syllabi for the various RYA quals / exams? Use of both traditional and electronic nav aids are all taught and examined on.