Newps writes:

I know the AIM is not regulatory, but I often find comfort in
following its suggestions in the hope that it represents genuinely
good advice. Do you think that this passage from the AIM represents
outdated policy that is no longer relevant?

Yes. I know that to be the case.

While that may be reassuring to *some*, others have had contradictory
personal experience.

For example, I have heard from a friend who worked as a safety rep for
a major airline at a major airport. Commercial airlines have had
their TCAS system yell to go around on short final when other planes
were taxiing or holding short but with their transponders on. So the
basic guidance to turn transponders on only on runways or when
airborne was reaffirmed. (Yes, some planes filter based upon radar
altimeters. That does not work at every airport, and not all
TCAS-type systems have RAs anyway.)

- FChE