As Becka already stated we don't have a pledge of allegiance to our flag, just the national anthem.
It was stressed every September from the platform though that as JW children we would not disrespect the flag, for example, and yes I am serious, by spitting on it! When was the last time you heard of a Canadian spitting on a flag!?
As a child the society kept on changing their minds with what we were supposed to do during the singing of the anthem. When I first started school I think we stood but didn't sing, then around grade 4 we had to leave the room and stand in the hallway, then that changed again around junior high and we stayed in the room but remained seated. Probably trying to determine what option would be the most embarrassing for us kids.