writes:

OK, 2 trivial examples, not crashing the airplane is an objective
and every place has fuel that fills the tanks to the top in zero time
when you get near the gas pump is an arbitrary rule.

Nothing requires you to avoid crashing your airplane, so that is not an
objective. I've seen people deliberately crash airplanes again and again in
the sim.

The gas pump isn't a rule, any more than a mountain is a rule.