Hmmm, triggering is pretty far out there. I tried doing a Night/Day system, but with a unit burrowed under your character you walk too slow, and without it I can't get vision any smaller (Without blinding, which I don't want to do because replacing a unit with one that says 'blind' on it seems unprofessional).
Is it possible to Create/Kill Map Revealers in game? because if you can then I'll just do that over your player for day and remove it over night.