The Canadian Government issues Travel Advisories to warn Canadian travellers about dangers/risks in various destinations. If there was a Travel Advisory in place for your destination, and you decide to book a trip anyway, you would have no coverage should your trip be cancelled or interrupted due to the reason listed in the Advisory.
If the Government issues an Advisory after you have already booked your trip and is still in effect during your travel dates; then you would have full coverage in place if you choose to cancel your trip. Always check the Canadian Government Travel Advisory website before you book a trip. It’s a good idea to check it again, just prior to leaving on your trip as well, in case something has come up.