Facebook should enforce that something along the lines of

    document.addEventListener('copy', function(e){/javascript:/.test(document.getSelection()+'') && e.preventDefault();}, true)

be added to every facebook page (via the fbml sandbox or something to prevent users from copying bookmarklets as they are profoundly dangerous and do much more harm than good on a social networking site. (Note, that the above code is just a prototype, it's quite incomplete in that it doesn't support IE and probably leaves a gaping hole for someone to use clipboardData.setText)