I’ve had one idiot instructor demonstrate the “benign ” stalling characteristics of an Evector sportstar down to 500ft. Overconfident prick.
Glider pilots are taught stalls and stall recoveries often at 1500 feet. None of this 3000 ft rubbish and gliders don't have an engine to help recover with minimum loss of height. 3000 ft just in case the stall turns into a spin was never the reason why 3000 ft was mandated years ago. That was purely for aerobatics and a stall is not an aerobatic manoeuvre.
On the other hand if you are in a Mustang fighter and you inadvertently hold the control column back in a stall the Pilots Notes states: "a wing will drop very rapidly and the aircraft will become inverted" "Power on spins should never be intentionally performed. As many as five or six turns may be made after recovery action and 9000 ft to 10,000 ft lost" Page 33 RAAF Publication No 780 dated September 1950. So there is one case you would be wise to practice stalling above 3000 ft..