The man talks sense
Most users never use Java apps, there's no sense in leaving it on, better to disable it and deal with the edge cases when someone actually needs it.
My SOP is to disable Java, Flash, auto fill and PDF plugins, most of the web works just fine sans flash since iOS support became a big deal, and in the cases where only flash will do, it's built into googles chrome browser which keeps it up to date without user intervention.
On a different yet related note, a good few years ago I knocked up a script that encoded a users IP and forum ID into the reply button jpeg on a MMOG forum, this enabled us to identify who was leaking screen grabs from private areas of the forum. /misspent youth.