if you have unticked all boxes in energy saver and under schedule everything blank there should be no way it can turn on itself as somebody needs to press the power button or have you got another program that could override these settings in energy saver maybe some sort of maintanance program or something like it ?
other option would be
Wake-on-LAN is an Ethernet computer networking standard that allows a computer to be turned on or woken up by a network message. The message is usually sent by a simple program executed on another computer on the local area network. Wake-on-LAN is also known as Wake on LAN, WOL, or sometimes WoL. It may also be known as Remote Wake-Up or RWU.
In case the computer being woken is communicating via Wi-Fi, the wake-up-packet can be sent via Wireless Multimedia Extensions (WMM).[1]. This may also be called Wake on Wireless LAN (WoWLAN).[2] Wakeup over Wi-Fi networks was not possible in previous implementations of Wake-on-LAN.
so if you use ethernet and there is another computer connected or wifi with another computer then it could be that computer that wakes up yours
i know that and it works great via ethernet, i drove a mate mad in the house with that feature(he is via ethernet connected to my router ) as as soon as i did hear his livingroom door closing, so i knew he has switched of his mac , then i woke up his mac ...was funny .. especially as he asked me to look at it and i got remote access, then i just let it play some itunes in the middle of the night ... who needs enemies when you got such good mates

(i did not do it every day and i told him about it after a couple weeks that his mac is not a new lifeform )
but if you are not connected via wireless or ethernet ...
...you are not sleepwalking are you?