There are three likely places where automated mail is sent to root: cron and anacron jobs, logwatch, and fixfiles.
cron output is usually sent to the user running the jobs. Under Linux, this output can be redirected to a different address by the MAILTO environment setting in the crontab:
anacron output can be similarly controlled using the same environment setting in /etc/anacrontab.
logwatch output is normally sent to root. This can be changed in the Fedora Core 2 or 3 configuration file /etc/log.d/conf/logwatch.conf:
MailTo = usernameor by adding the above line to /etc/logwatch/conf/logwatch.conf under Fedora Core 4.
fixfiles output is also normally sent to root. This can be changed in the file /etc/cron.weekly/fixfiles.cron:
The above instructions are correct for Fedora Core 2, 3 and 4. They are likely to work under most other varieties of Linux, but check your man pages.
Wherever you direct the output of root cron jobs and logwatch output, it would be irresponsible to ignore such output.