I don't think a law was needed. Living in the north country, it just makes sense to put them on. Quebec went a bit over board though. I believe it starts next Dec.15th that if the snow tire you have now does not have the snowflake symbol on it than you will be fined and have to purchase the tires with it. The winter tires on my car and truck don't have the symbol and they are just like new.
So for next year I am f**&^$*
Beer (adrien)