I suppose it has alot to do with the Aircraft you teach in. Today I had a student nearly spin me at less than 2000'...I was not impressed but I"m glad it nearly happend because it brought the problem to my attention.
I don't teach them to use the ailerons in the recovery...I mean before the stall....even before the buffet.
As I said every aircraft is different, the 172 is harder to spin as is the 152 (A good thing me thinks!!)
I did my spin/upset/aerobatic training in the Zlin...Czec made...very nice and it has the trait that you won't spin if you're co-ordinated. I could understand in heavy updrafts the relative wind may change and cause the AOA on each wing to change resulting in a spin. I've always stuck to the concept that a spin needs 2 things
1)Stall
2)unco-ordinated flight
if you don't have both you won't spin. But that's not to say that you're rudder trim tab could be off and your Turn co-ordinated not calibrated properly then I agree...you will spin, but as far as the theory goes I tend to stick close to that.
There is one major thing I've learned with aviation though..............As soon as you say never it'll bite you in the A$$!!
cheers fellas