Leaving the controls
I have left the controls of a running helicopter when picking up pax.
With the frictions tightened and sitting at idle, it was the safest way of conducting a pax briefing prior to loading them. I don't like the idea of trying to load pax by waving at them and hoping that it will be safe...
It's not a common occurrence, and before there is a stream of posts about briefing prior to arriving, or at the time of the booking, consider the surprise/gift flight. In my case an anniversary present. There was no opportunity to brief the wife prior to my arrival. After the shock of the gift and the husband's exuberance have both past, I conducted a briefing, loaded and flew. Should I have shut down? There would still be an element of danger as I ran it down for 2 minutes...