Like PC use at work, there can never be a reasonable expectation of privacy with pagers, cell phones, radios, tablets, what have you.

Doing dicey personal business on company equipment is industrial-strength idiocy. A fellow employee at a company I used to work for used his desktop to download numerous pirated DVDs. Finally one of the Publishers called our boss on the carpet for it. The worker was fired as soon as this came to light, and rightfully so. The boss had to do some fancy footwork with the Publisher to avoid prosecution. Traffic to and from company-owned equipment is absolutely company business.