Have you ever tried to ride a bicycle with your arms crossed over? It doesn't work, as your learned responses are too ingrained.
I doubt that there would be too many people who could fly a cyclic with their left hand and work the collective with their right, especially in the rapid-response world of a check ride. I have tried to hover a Robbie from the left seat, using my cyclic and Bloggs' collective, but it was hopeless. Anybody else able to pull off an auto that way?
