Dennis should have first confronted Zack about the issue to find out what was going on. If he could not get any satisfaction there then taking the issue to Tim would have been appropriate. Another solution that could have taken place would be for Dennis to report the issue to an ethics hotline in order to have it investigated by neutral parties. This of course could only happen if the company has such a line and policy in place. This type of system helps by providing employees with a way to report things that happen within the company without having to have confrontational discussions with possible offending parties. Reason

If an electronic mail (e-mail) system is utilized within a business, the employer owns it and is permitted to look at its contents whenever it wants. Messages that are sent inside the company as well as those that are sent from any terminal to another company or from another business to any terminal in the company can be subject to monitoring by the employer. This also comprises web-based email accounts as well as any instant messages that are exchanged. Generally, workers should not take for granted that any of these activities are not being looked at and that they are private (Workplace Privacy and Employee...

It has been determined by many court cases that the employer has to right to look at what is coming and going via their email systems.
Comments/Thoughts

This case brings up a lot of good issues that face people in the business world every day. They know there are rules and they know that they shouldn't be doing certain things, but hey do them anyway. If this is the case then these people also need to be able to face the consequences for their behavior. But if an employee has truly not done anything wrong in accordance with the policy that they have been communicated then the company should not go back on that policy when it suits them. The problem that I have with this case is 1) the employees were told in an orientation meeting, presumably by someone in HR that personal emails were fine and 2) I don't think monitoring email and reading email is the same thing. I also have a problem with the fact that they company does not appear to have any ethical hotline or complaint program in place to assist their employees when they are faced with difficult issues at work.

Reference

Workplace Privacy and Employee Monitoring. (2011). Retrieved from http://www.privacyrights.org/fs/fs7-work.htm#4