In Montreal, the possibilities and probabilities of getting, robbed, mugged, abused etc. are very few as compared to other major cities of North America. Montreal is a very safe place and people are very friendly, they go out of their way to help you or show you the way. So,  feel free and relaxed; as the old Arabian proverb says, "Trust in God, but tie your camel", just take care of your cars and your goods like you do in your home town, after all it is a city of 3.5 million people and not angels. So remember to lock your car, roll up the windows, and make sure you do not leave valuable items (or items which look like they might be valuable, but aren't, e.g. broken cameras, empty boxes with labels suggesting expensive contents) in plain view inside your vehicle.