My tuppence worth...
Speaking from personal experience when I was almost chopped into small pieces by an ATP and colleagues gripping the concrete with their finger nails when a 747 taxied before clearance and the no.2 engine went over the top of them!
We rely on you guys to follow SOPS to keep us safe.
sorry, but I do not see the point. Why wait for the hand signal before doing the checklist???? You do the checklist (you are not moving and the park brake is set) then, AFTER you receive the hand signal you request taxi.
Some A330 operators set flaps after engine start, this sends the engines to flight idle. Not particularly unsafe perhaps but on a greasy wet night, it's another hole in the cheese.
Perhaps they were trying to be courteous to the other ramp occupants: That's 20 fewer seconds that everyone else has to look at a hideously ugly aircraft.
