I had this problem with mt desktop PC, which would randomly wake up from hibernation in the middle of the night. My computer was in my bedroom, so this was very much a problem since the bright screen would always wake me up. I couldn't even shut off the screen since it didn't have a power button (Apple Thunderbolt display).

My solution was to reach around to the back of the tower and cycle the PSU power switch after hibernating the PC, every time.