My mirrors are definitely not loose. Like I said, the bike just vibrates enough to make anything beyond a couple hundred meters back a total blur.
If you guys think that the crappy rider and driver training courses we get in Canada are the gospel, you're welcome to your opinion. But did you know in Europe a shoulder check is an automatic fail on the exam? That's because there they teach you how to properly set up your mirrors, and they expect to keep your eyes on the road at all times. Craning your neck to look behind is one of the dumbest moves possible, because by the time your eyes focus on what's to the side of the vehicle and then back what's in front a good 2-3 seconds have passed. A lot can happen in that time...
I can tell you in my car the centre mirror covers the back view and the side mirrors cover the blind spots. I have a 180 degree view of what is happening behind and I NEVER have to take my eyes off the road to do shoulder checks. If you look in the centre mirror and you see the same thing in the side mirrors, they are set up incorrectly. Ironically that is how the vast majority of people set their mirrors up, and then wonder why they can't see the blind spots. On the bike it's a bit tricky because obviously there is no centre mirror. But the side mirrors still cover the blind spots to a large extent.
I really don't expect to change anyone's opinion on this matter, especially since shoulder checks are mandatory on all exams in Canada. I just know what works for me and most of the world. Jim Kenzie from Toronto Star has been advocating this technique for years btw.