My Dad has his own tales of being streamed for instructor after Basic Flying Training on the Commonwealth Scheme in Canada. He was there from 1942 to 44, initially as a Sgt then commissioned to Plt Off before heading back by convoy to train as Battle Casualty Replacement on Dakotas after Overlord.
Apparently if you were commissioned and achieved 1000 hours instructional in one year there was an AFC in it for you. If, however, you achieved this total while non-commissioned you were simply taken off instructional duties for a short while and told not to hog the flying programme for the other blokes.
He loved Canada and the Canadians; his tales of flying around Saskatchewan and Manitoba in Airspeed Oxfords, NA Harvards and DH Tiger Moths - and what he got up to later - were a major reason why I chose this way of life.
Not that my own experience of creamies was that good - just as many have described earlier. My initial Fg Off QFI - initials DH - had difficulty working out why ex-squaddie Thud (with no flying experience) didn't pick things up as quickly as he had. Cue early instructor change, and all went well after that. On reaching the rotary world, I was delighted to find that every QHI had been around the buoy for a few years before being allowed to inculcate the newbies.