This comes up time and time again. The search function is your friend.
Bottom line is usually that a few individuals think they have found a way around the law by selectively interpreting the law in their favor. These are usually the first people that will flagrantly flaunt beating the system... until they get caught, at which time they will realize how unforgiving the law can be when it comes to firearms.
In the end, I say go for it. Those that feel compelled to do so should not be coming on here asking other armchair lawyers for their interpretation of the law, as they seem to already have their mind made up.
Check the links below and see how this has been discussed to death.
http://www.canadiangunnutz.com/forum/showthread.php?t=129060&highlight=backyard
http://www.canadiangunnutz.com/forum/showthread.php?t=405579&highlight=backyard