Any body here land flap 20 as a matter of routine?
A number of schools do and much of it comes from the C150 which has 40 degrees of flap. As the aircraft will not go around in that configuration it needs to be emphasised to the student that the flap has to be retracted. Many schools teach 20 flap on the C152 to avoid the student having to retract flap to 20 in the event of a go around. Unfortunately, if you don't teach it the pilots will be poorly placed if they attempt to go around from a short field landing or fly a C150 or early C172. I would expect a candidate on a test to use 30 degrees flap. Once they are experienced they can elect to use flap to suit themselves. Having done lots of C152 landings with up to 35 kts crosswind, the aircraft lands best with 30 degree flap.