In my opinion a filing cabinet typically would not meet the "difficult to break into rule" pretty simple to bend a cabinet draw and get inside or cut/smash a hole in the side. If someone broke into the cabinet you would have a hard time arguing it was OK.
This is a really good post imo.
And personally I put trigger locks on my pistol because I have 2 curious little kids running around the house... but you don't have to by law...
http://www.canadiangunnutz.com/forum/showthread.php/963639-Safe-Storage-for-Dummies-%28With-Pics%29?highlight=safe


















































