Hmmm...personally I think you are being a bit paranoid. Yes, the US has areas that are less than desirable to visit (as does Canada), but in general I dont think you need to be scared to visit. IMHO, people traveling to Canada with loaded weapons is not because of a fear of being robbed, but rather a fear of being eaten by huge grizzly bears.
As far as seeing people carrying guns, generally speaking, criminals don't carry their guns in plain site. If you can see the gun, its almost 100% certain that person is legally allowed to own that gun.
Also, dont be afraid to look us in the eye! Most of us have zero issues with Canadians (even when it comes to hockey and who is better!). We regularly interact with our friends up north and welcome the opportunity to break bread and share stories with you around the camp fire!
Jon