Wearing a backpack and riding is stupid In my personal opinion. Seems to be mainly a sport bike thing here in nth America. Europe /Australasia tend to have racks that can be easily removed. They do sell one here.. Forgot the name, but it's hard to find.. And like I said the nth American is all about the look.
Been in this discussion so many times over the years.. Just strap the back pack to the rear seat with a bungy.
A backpack could be unbalanced which would affect riding and handling through the turns also add to the "sail effect " with wind forces on the rider..
I've seen riders go down with a back pack.. During a slide, it will cause you to tumble and depending on what's inside.. Break your back and or contents.
Interestingly there is a ton of discussion on the subject on the www.
I get that riding with a backpack is uncomfortable, but how is it stupid from a commuting standpoint to the point where you're "Off balance"?
Yeah, if you let your backpack hang to your *** like a high-school kid, it could shift around when cornering, but how "off balance" could you realistically be where it effects riding in a straight line in Ontario?
Top boxes would be preferable, but it comes down to $$, and usually a few hundred dollars at that.
I have no idea where you're coming from in regards to the "North American look"... Who actually WANTS to ride with extra luggage...?
As for going down with a backpack... Please refer to the video posted of me going down with my backpack. A laptop would simply be crushed if the rider should land on it. Falling on the street, there are a lot more that you can collide with that can break your bones than whats in your luggage. (Unless you decide to carry sharp or small/hard objects - ie. screwdriver).
If the argument is contents breaking, having a backpack with a bungee net wont save it, carrying it in side cases wont save it, and the only option is a large enough top case.
So far every person I've seen go down with side-cases, had them crack and open up throwing things everywhere while going less than 40km/h...