Sorry chaps about the duff gen (locking outboard ailerons)
Trouble is I'm flying DC10s at the moment and the last few years.
The phenomenon is called 'recency' when you forget the previous stuff - except in a crisis when you revert and confuse the hell out of yourself!
The DC10 DOES lock the outer ailerons when the flaps are up unless you get a stall warning.
Vortex generators though I still think are there to regenerate the boundary layer and retain roll control in the event the inner wing section stalls.