Ok, I've looked into it, and I've come to the same conclusion I've come to before, but with more certainty this time. (I forgot about last time, or was just not very sure I wasn't getting it confused with something else that was similar).
It seems ANY game option that is set after tick 0 (i.e., anything not set in InitProc) other than FreeMoraleLevel will cause this to appear. This will include any of the ForceMorale commands, as well as things involving daylight. There is also a set game speed that can trigger this, but I would assume it's only used in network games to force everyone to the same game speed.
Basically, the game keeps track of when the last game option was set (other than free morale level) and if that value is ever non zero, it'll print the "CHEATED GAME!" message.
So, it seems the way you plan to write your level, it won't be possible to get rid of that message. At least not if you restrict yourselves to the usual Outpost2.exe exports. You can always do some mem hacking to remove that message if you really need it. But then, I'd suggest asking yourselves how important it is to freeze morale while you're relocating your base. Could you settle for just unfreezing morale once, when you first deploy a CC?