I've just been doing a few stalls for my PPL.
I found out that even thought the student or the instructor put the aircraft into a stall deliberatly, doesnt mean that it is controlled, after all, if you had the aircraft properly under control it wouldnt stall.
However, when my instructor demonstrated a stall, it went a bit worse then he hoped for, we had a bad and sudden wing drop, recoverable, but still, very fast and sudden.
So when doing stalls especially with flap, be ready for anything. Wing drops can be slightly worse in bad weather conditions.