Will you ever have a problem driving with expired or temporary tags?
I don't think so. If you travel to Mexico there going to pay more attention to your license plate than your tags. I've been told you should always carry international insurance too when in Mexico,there are areas you wouldn't want to get caught without it. I don't know if Foreigners are still targeted by the Federalies like they did years ago. Your fine in Canada though as far as British Columbia goes the police there won't bother you unless you do something really really stupid.