It looks like the Mac OS X 10.4.9 update updates sudo such that it now no longer references “We trust you have received the usual lecture from the local System Administrator.”, probably because many people don’t have a local system administrator. Nor does it warn you that with great power comes great responsibility. Certainly there were lots of people searching on that phrase, presumably to work out what the “usual lecture” is. Now sudo gives
WARNING: Improper use of the sudo command could lead to data loss or the deletion of important system files. Please double-check your typing when using sudo. Type "man sudo" for more information. To proceed, enter your password, or type Ctrl-C to abort.
Which is probably more useful if you haven’t experienced sudo before. I also note that typing ‘help’ at the bash commandline now gives you something better than “command not found”