Some states have begun to require notice to employees before monitoring. I am not an Arizona attorney and cannot tell you if Arizona is one of those states. The movement began with a California statute.
Generally, though, an employer can monitor on the premises. There may be some limits on phone calls, but, other than what my colleague said, very little else.
[This communication is intended as general information and not specific legal advice, and this communication does not create an attorney-client relationship.]