For example, even though employees are well within their rights to send emails or text messages of a sexual nature while at home, doing so on company time and/or using your company’s Internet connection could potentially make your business vulnerable to sexual harassment claims.
If these suggested rules regarding employee smartphone use sound confusing, just reinforce this guiding principle: If an employee would not use his smartphone in that manner with a supervisor standing behind him, then it is not work-related and probably not permissible.
Source: www.Findlaw.com