I'm a Canuck too, from Oakville.
They did have theme nights on the Grandeur but the only one that you really should think about is the Caribbean night. The dress in the dining room that night is casual or "Caribbean". You will see by the waiters attire which night it is and what the theme is (ie Italian etc.) but the only time I saw folks dressed for theme was on Caribbean night with the guys in lots of bright colored shirts and girls in sun dresses
Hope this helps!