I have noticed some crew, in excited anticipation of your next call, place their hand either on or very close to the controls, eg. flap lever. So guess what happens when you sneeze!!
Agree. Quite common observation in the simulator. Can be most distracting as well as potentially disastrous. Similar to a B737 PM backing up the thrust levers until V1 during the takeoff roll with his hand when it is unnecessary since there is no external friction nut like a DC3 where the throttles can slip back if the fiction nut is not working properly.
The danger of unnecessary backing up until V1 with the hand behind the thrust levers (or throttles with some types) in the 737, is that a sharp closing of the thrust levers by the PF if he perceives an abort is necessary and there is no time to politely request the PM to kindly gets his mitt out of the way so an abort can be accomplished without delay.. This may jam the PM's hand between the back edge of the thrust levers and the adjacent start levers. Very painful and worst case the PF may not be able to fully close the thrust levers to idle if the PM's hand is in the way.
There are so many gimmicks perpetuated by some pilots either brought across from previous types or copied during simulator training. While this all sounds a bit trivial now, it can be distracting to another crew member. A PM hovering over the controls with feet on the rudder pedals is another unnecessary and distracting habit one frequently sees in the simulator.