[root@risby]# strings /usr/bin/sudo|grep privacy
#1) Respect the privacy of others.
Happily, however, my
man sudoers admits of the string
lecture_file which it says is the
[p]ath to a file containing an alternate sudo lecture that will be
used in place of the standard lecture if the named file exists. By
default, sudo uses a built-in lecture.
So see if your sudo supports that, and if it does, set it to a particular filename with e.g.
Defaults lecture_file = /etc/sudoers.lecture
and put your lecture text in that file. You may find this easier to test, as I did, if you also do
Defaults lecture = always
which will display the lecture on every invocation of sudo. Otherwise you may run out of accounts which have never sudo'ed while you get this right!
If your sudo is old enough not to support these variables, you will need to recompile from source. That has its own attendant worries, so you will wish to think very hard before doing that purely for cosmetic reasons.