Preventing Email/Net Monitoring Abuse

Most companies seem to be employing some kind of monitoring software or policy for their email servers or internet connections.

What I am wondering is how do they prevent the person in charge of collecting this data from abusing the privilege? Specifically, the user with access rights to read other people’s email.

Is there any way to report on that kind of activity that doesn’t rely on manually reviewing the security logs? How would you track any email abuse from emails that get forwarded to an account outside of the company?

thanks in advance,

Scott