I will be adding this clarification into Core Rules 7.6 Actions. It supersedes anything that says otherwise. 
(Obviously, my comment below does not apply the Solo Assistant but is a clarification for face-to-face play.)
CORE RULES 7.6, Action STEP, ADD to the end of the section
If a player activates a unit or stack and does not elect to execute a Direct Fire or On-Board Artillery Action with it, then the player may start to move it before finally declaring whether they are using a Movement, Move and Direct Fire, or Assault Action.
The player must finally declare the action of the moving unit or stack to be:
- an Assault action, when it arrives in a hex adjacent to a hex it wishes to Assault, and then declares it is entering the adjacent enemy hex to execute the Assault itself; OR
- a Move and Direct Fire action, when it concludes its Move and then attempts to execute the Direct Fire portion of the Action; or
- simply completing its Movement Action.
When such an action is finally declared, then that Action is completed as usual per the rules for the relevant type of Action, and Ops Complete markers are placed as indicated in those rules.
Active units or stacks moving in inactive enemy units' LOS, and with or without a declared action, are subject to Opportunity Fire as usual.
Design Note: It is a gentleperson's game; we typically do this in play without haggling, it is a natural progression of play, but there have been requests to codify this. What this does is NOT telegraph a unit or stack's intention by artificially declaring an action, which gives an unrealistic intelligence advantage to inactive enemy units looking for chances to execute Opportunity Fire. Inactive units see them coming, but do not necessarily know what the active enemy is going to do.
(Obviously, my comment below does not apply the Solo Assistant but is a clarification for face-to-face play.)
CORE RULES 7.6, Action STEP, ADD to the end of the section
If a player activates a unit or stack and does not elect to execute a Direct Fire or On-Board Artillery Action with it, then the player may start to move it before finally declaring whether they are using a Movement, Move and Direct Fire, or Assault Action.
The player must finally declare the action of the moving unit or stack to be:
- an Assault action, when it arrives in a hex adjacent to a hex it wishes to Assault, and then declares it is entering the adjacent enemy hex to execute the Assault itself; OR
- a Move and Direct Fire action, when it concludes its Move and then attempts to execute the Direct Fire portion of the Action; or
- simply completing its Movement Action.
When such an action is finally declared, then that Action is completed as usual per the rules for the relevant type of Action, and Ops Complete markers are placed as indicated in those rules.
Active units or stacks moving in inactive enemy units' LOS, and with or without a declared action, are subject to Opportunity Fire as usual.
Design Note: It is a gentleperson's game; we typically do this in play without haggling, it is a natural progression of play, but there have been requests to codify this. What this does is NOT telegraph a unit or stack's intention by artificially declaring an action, which gives an unrealistic intelligence advantage to inactive enemy units looking for chances to execute Opportunity Fire. Inactive units see them coming, but do not necessarily know what the active enemy is going to do.
