Unfortunately I was that man - the QHI what bent a Gazelle when debriefing a student as described by Crab. Not only that, but it all happened almost exactly the same way as Shy Torque described - the only difference being I was in a confined area, and transition was not a good idea.
Yes I had done the 'wrong hands' flying on CFS(H) - hover, circuit and landing - and had not found it too onerous within the confines of an airfield. Unfortunately when it went wrong it was the 'natural reactions' that took over instantaneously and made things infinitely worse in both pitch and roll; even tho' my own gyro quickly realised what was wrong all I was left able to do was lower the lever as the skids went level (power up potentially into the trees was not an option) and we hit the ground hard!
One of those wonderful 'I learnt about flying from that' moments. Hindsight is a wonderful thing, and I don't think I ever did it again in the hover, but at the time it did not seem 'wrong'. I might add this was in 1990, but is now used as the reason for the 'wrong hands' demo; when I did the course, in 1986, it was because of the frange at Chetwynd.
One other learning point; if there is a nearby farm send your student to make the phone call (days before mobile phones) - that way he gets bitten by the farm dog!