I now teach turn backs on the UH advanced PPL course - not so people use a turn back, but so they see how hard it is to do! This is of course done at height with an altitude (usually a round figure such as 3,000') as "runway height", people then come away with a realistic idea of what is and is not possible, how quickly you need to react and also how much you need to plan ahead if you are going to consider using it if you need to (i.e. on climb out at SOU where there are not many decent options!).
