Activating to move, not moving

[Poor Yorek]

Rule 3.13 "Movement" includes moving (5.0), digging-in (16.2), limbering/unlimbering (5.63) or attempting to recover morale (14.4).

When you activate and declare a "move" action for the ENG (amongst others), you do not have to determine what, specifically, you are going to do until you come to that piece. Personally, I think a "no move" is a viable option for "moving," but if someone throws a spittle-flecked-nutty about it, just make a morale check (oh gosh, I stay in good order) or dig-in: nothing is lost as you are going to eschew the action anyway by placing the M/F marker on the unit.

If you move or whatever next turn, nothing is lost by the previous digging-in declaration.