Tolerating an un-airworthy aircraft. Wing drops at stall

[Judd]

Australian Flying magazine November-December 2020, published an article by the editor Steve Hitchin where he talks about brushing up his stall recovery skills using a Piper Warrior at Victorian counttry flying school. The article was well written and entertaining until the bit that said "We had deliberately chosen a Piper Warrior with an unrelenting habit of dropping the right wing at the stall. No point in making this easy" wrote the author.

Later in the article his instructor said " This aircraft has a tendency to drop a wing to the right in a stall"

Certification flight tests by the manufacturer's test pilot require the approach to the stall be flown at one knot reduction per second. In other words not a rapid loss of airspeed as might be expected if the nose was initially pulled up too quickly. In addition the maximum wing drop permitted at the point of stall is 15 degrees.

While the article does not record how many degrees of wing drop on that particular Piper Warrior constituted "an unrelenting habit of dropping the right wing at the stall", the description by the author would suggest it was considerably more than 15 degrees.
That being the case, assuming the approach to the stall was correctly flown at one knot per second speed reduction,the amount of reported wing drop would indicate the aircraft was un-airworthy and the maintenance release so endorsed.

Sharp wingdrops at the point of stall could be due to any number of reasons. For example, damage to the wings, pilot faulty technique, icing on the wings or defective or incorrect rigging. The latter is the most likely in this case.
Rogue flying school aircraft with a reputation for a marked wing drop at the point of stall are often not only tolerated by flying school operators but even encouraged to be used for stall training. Perhaps this is what the author implied when he wrote "We had deliberately chosen a Piper Warrior with an unrelenting habit of dropping the right wing in a stall?" Was this defect recorded in the maintenance release? Buckleys..
An unexpected sharp wing drop during hold-off could lead to an accident; particularly if the aircraft is flown by a student pilot.