Skid, you might want to think about investing in an electric can opener. I love mine and I don't think you can get it to work if the can's not the right way up.
Also great if you have arthritic hands (as I have).
yeah and watch out for the top and edges if you eat out of the tin -
they ' re sharp !
having regularly tried to open the wrong end of things even before I lost some of my sight - alot are NOT symmetrical
so if you cant get the opener on - read label - and um if you cant then it MAY be upside down