pgbnh wrote:

It is common wisdom, and often common sense, that if a full deflection of a
CDI (or GS) is experienced, a missed approach is to be flown. But a lot of
people seem to think that it is REQUIRED. I have had a CFII tell me it is
required. But I can not find anything in FAR or AIM that states such a
requirement.

Again, in a lot of cases I can understand why to do it. But I can also
imagine others where it might make just as much sense to recover the
approach and not go missed.

Can anyone point me at a rule that requires a missed?

The rule is implied. The procedure is an FAR. If the needles are fully
deflected you are no longer flying the courses or altitudes specified in the
procedure. Thus, if you don't miss you are continuing the procedure without
following the requirements set forth on the approach chart.

The feds won't bust you for violating Part 97, though, they'll bust you for
careless and reckless.