I have only used the Collins HSI's in large turbofan airliners to fly backcourse approaches, Airplay, so I can't really comment about other aircraft.
In these aircraft that I have flown (with the Collins units), the front course QDM is always selected, and correct sensing is automatically provided.
No separate annunciation was provided...it was up to the pilot flying to know where they were on the approach.
An interesting observation, from many years ago, might interest a few younger folks here.
Location...PanAmerican B707 non-visual simulator, SFO
, circa 1973.
Individual under training... a Flight Engineer upgrading to First Officer.
Approach...backcourse approach to runway 11, OAK
The trainee was hand flying this approach, using the flight director (backcourse mode), but instead of remembering that there was no glidepath, flew the sim right into the 'water' of SFO
bay...whereupon the instructor (a very senior PanAm Captain) tossed a small cup of water on this guy, and mentioned....'hey sport, you just got wet, and no doubt killed a few passengers in the process.'
The other crew members had been told to keep quiet, to see just what this guy would do on his own.
Airline training is designed to keep the incidents/accidents in the simulator, where they should be, and is no picnic for new guys moving up the ladder, then or now.