That is exactly the kind of skills that should be taught but are not....
Certainly someone is very much remiss if it's not taught! It's not really a skill; it's called a gross error check and is very basic stuff.
I recall when the RAF first fitted Decca TANS nav kit to our helicopters, some pilots thought all they needed to do was to plug in a diversion grid reference or lat/long and get going on the heading. I pointed out to some who really ought to have known better that rubbish in = rubbish out! A few learned the hard way about fuel planning in that you can't always fly in a straight line between two points, for a number of reasons.