If you agree it's the proper thing to do, does it matter if it's required or
not?

He doesn't. He agrees it's =often= proper.

If you have full deflection, you don't know how far off course you are
(although you do know how far off course you aren't). You don't know
what the terrain clearance is, since you are no longer in the protected
area (although I believe "some" protection is provided for "some
distance" outside the zone). So, if you don't know where you are or
what's below you, then continuing the approach doesn't make sense, and
the "careless and reckless" clause could be applied.

However, in some circumstances, for example in broken clouds and with
some ground contact to give you terrain assurance, when you =just= went
full deflection so you do know where you are (it's just not where you
want to be), and a low fuel or other critical situation in busy
airspace, and you know why you went full deflection and can come right
back (you didn't just zone out), it =may= make more sense to recover the
approach.

I know of no specific rule for part 91 ops that requires a missed.

Jose
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