Canada is definately not a good example for this, reason being that outside of Ontario and New Brunswick, almost every province is purely English speaking. Our bilingualism is at federal level only (Manitoba is on the fence here, but New Brunswick has it at both provincial and federal).
There are what I think insane rules in Quebec about French, including stores on one side of the street having to be completely French.
Sorry, to get back on topic: Should they? That would all depend on what language. Spanish would be the language I would see being the one to teach children. But even then...