Our venerable Arrow still has (they were disabled in later models and then removed altogether) the Auto extend feature in which, if the manifold pressure is reduced to, or the airspeed drops to, pre landing values, a klaxon loud enough to wake the dead sounds, warning that the gear is not down.
On our Arrow, both the stall warner horn and and auto extend horn are loud enough to break through the best ANR headsets.
(Indeed on the ground, when preflighting, the stall warner can be heard 50 yards away from the aeroplane).
Then, if you ignore the klaxon , the gear drops automatically in pretty short order, so technically at least, it should be impossible to land with the gear up.
Later models had a pin which locked this feature, but an amber light on the panel, just above the u/c green indicator bulbs, flashed intermittently all the time the pin was engaged. This I think was sufficiently annoying for Mr Piper to remove the autoextend feature.
I think it is a bl oody good idea to have auto extend: fortunately 'it never happened to me' while landing but it scared the cr ap out of a wet behind the ears AFI who had never flown an Arrow when he was doing my 2 yearly check flight:
Despite my telling him to hold the auto extend lever up while doing stalls and slow flight, he said 'no it'll be alright' >
So when we approached the stall with the stall warner blaring, the additional klaxon sounded and the gear came down with a thump: I had to lower the nose smartly because of the extra drag effect on stalling speed, and it was all too much for him.
The only serious moment when auto extend would be a BAD THING would be on ditching: Sudden unexpected appearance of the gear just before hitting the water could seriously spoil your day.
So, when flying over water RHS pax is shown the gear extend lever just above the flap handle and briefed, if ditching required, to haul it up with all his might until we are nicely bobbing on the waves.
Cusco