The "subscribe to this bug" link (eg https://bugs.edge.launchpad.net/bzr/+bug/144522/+subscribe) has 'Cancel' and 'Confirm' buttons, in that order. For some reason I tend to press the Cancel button, which is on the left. I realize the placement of Cancel buttons is inconsistent between platforms, programs in Ubuntu, and Gnome releases so I won't attempt to argue that it should be on the left or right.
However, as far as I can see this is the *only* Cancel button in Launchpad: it's not on the "subscribe someone else" page or any number of other similar pages. If in every other case navigating away from the page suffices why is there a Cancel button here at all?
How about just one pushbutton "subscribe me to this bug" and people can push it or not.