Forget confirmation, Ctrl-Q shouldn't exist in the first place. An keystroke that can close your whole session and is near-identical to another, very common keystroke is a design flaw, period.

Same with the backspace key activating the back button. Using these keystrokes for these purposes should be considered harmful.

Ctrl-Q is so harmful that I've long fantasized about hacking whatever driver in the kernel that controls the keyboard and having it ignore whatever signal the keyboard sends out whenever you press Ctrl-Q and not even pass it on to userspace.