The is true unless you enable input or output logging in the sudoers file. Then it logs those specifically in the sudo-io directory. From what I have found since this post is that you can change it upon install by adding the following to the configure script:

--with-iologdir[=DIR]

By default, sudo stores I/O log files in either /var/log/sudo-io,
/var/adm/sudo-sudo-io or /usr/log/sudo-io. If DIR is
specified, I/O logs will be stored in the indicated directory
instead.

But as with sudo verison 1.7.5 and later there was an update to be able to change this setting via the sudoers file. I still am looking for a possible solution to change the sudo-io directory without re installing sudo.