Activating a precondition will draw grid power regardless of any rate/time/location based charging restrictions. It's all completely overridden at that point.
We are in the exact same situation as you, also located in Ontario. My wife leaves every morning around 7:30AM (and the Volt is configured to avoid the 7a-9a peak electricity period for normal charging) but it does indeed draw over 3KW from our grid (as verified on my whole-home wattage display) during precondition.
-Mark, Ontario Canada