A player argued that as his infantry ( loose or close ) had the fleet of foot characteristic, he could disengage as a SK unit.
As the characteristic only precise that the unit moves as a SK unit , the question is open ?
IMO it is pretty clear.
The characteristic says that with FoF the unit moves using skirmisher movement distances but get no other benefits - i.e. they are not skirmishers/SUGS for anything.
So for moves whilst you move the skirmisher distance, you do not cost the movement as skirmishers - so a break off is done using the TUG columns for which card colour you need.
TUG column but 2 or 3 MU back
Which means how far to the back, SK move or INF move
Ah, sorry, got the wrong end of the stick with the question.
For Fall Back M13 move as they are not actually skirmisher infantry as per above so cannot be a M12 move - so 2 BW max.
But you do get the advantage of being able to an F3 against non-FoF infantry
Indeed - unless fighting skirmisher infantry (not common but can happen).