Indeed, and I hadn't thought properly about it until XKCD, as often, shone a bright light on the nonsense that is root password paranoia:
http://xkcd.com/1200/Which leads me to better respect what Ubuntu was doing with the Yama ptrace scope limiting (which prevents you from debugging a running process even if you're the same user, unless you change a /proc/sys var), and why the Weyland developers are wringing their hands on how to properly handle graphical app communication privileges (because currently, X11 allows any process to view any other process's display and events, including keyboard input)