I have this problem: the mode selection wheel on my Canon 5D II is much looser than I'd like and changes values randomly as I take it out of the camera bag. Same thing sometimes happens to the autofocus / IS selector on my lenses. Is there a product or a technique for dealing with this annoynce?
And the answer is this Canon realized defectiveness of their design, and now offers a $100 option to switch to a better button. This sucks, but hey, what can I do.
I haven't experienced that with mine. The stops are quite distinct, and you have to apply a lot of pressure if you want to turn it by pressing on one side (as opposed to gripping both sides).
If you are able to turn it by just putting in your camera bag, there is probably something wrong with it, and you should contact your dealer. Judging from the sound and feel, it's a ball and spring mechanism, in that case it's not adjustable in any other way than modifying or replacing the spring.