I've never slept in the terminal at YYZ but I did sleep in the terminal at ORD a few years back courtesy of a weather delay. They kept playing the announcements all night ... which not only kept me up, but drove me to the edge of madness. "All bags look alike. be sure you have your own bag" ... "If you see something suspicious ..." ... and of course, ""The white zone is for immediate loading and unloading of passengers only. There is no stopping in a red zone."