If you use a one-way lamp module or wall switch, they don't remember their previous state, so they should stay off when power is restored (assuming power was out for more than a second or two). However, they ususally can survive a brief blip (less than a second or so), and may remain on.
I actually have a solution for the opposite - to turn things back ON after the power goes out. It is a complex series of conditional macros, triggered by a powerflash on which I connected the contacts together. If power is out for a few seconds (long enough for the capacitors in the Powerflash to discharge), then it sends an M1 when power comes back on. Based on day and time, the macros will turn on the appropriate lights and modules.