eah something smells fishy here.
Unless you were super slow on descent the prop would have to be feathered for it to stop windmilling.
You obviously have not flown anything with a Rotax 912 up front, they drive a gearbox about 2:1 ratio, its quite easy to stop the prop and still be well above stall speed inthe Microlight/VLA/LSA types they are usually fitted to.
Ive had an instructor do exactly the same as shown in this video on a check flight, Its an important skill to have and maintain
P.S. I am quite certain the instructor had pre scanned the area and had a field planned for the eventuality that it would not re-start