Confusion about when it's my navigation, and when it's ATC

Recently, Mxsmanic posted:

Neil Gould writes:

If the real aircraft can't get to a FL, *any* representation of the
aircraft's behavior at that altitude is incorrect.

Not so. The aircraft could be placed there by another aircraft, in
which case it would have some sort of behavior that presumably could
be simulated. It just can't get there under its own power. Slewing
functions in a simulator are the equivalent of carrying the aircraft
to that altitude in real life.

That is an absurd scenario, and of no use in the simulation of the real
aircraft.

Bottom line: if the game allows the aircraft to reach a FL that is twice
the service ceiling of the real aircraft, then the engine is modelled
incorrectly. If the engine is modelled incorrectly, everything else about
the aircraft's behavior in the game is suspect. Of course, it is a
non-issue for those of us that actually fly.

Neil