In Civilization IV (and earlier) you could end a turn not having moved/actioned all of your available units. For example, if you want to leave some units in place for a turn or two, without having to explicitly tell them they have no orders – simply by clicking a button in the UI.
In V, it now insists that ‘A unit has still to move’ and I have to explicitly tell it to do nothing. I couldn’t see a means of telling the game to end the turn immediately – is there one?
You can finish your turn with Shift+Enter at any time.
I didn’t observe what happens if 2 units “illegally” stacked (I.e. building a unit in a garrisoned city).