It's illegal for an employer too, without saying, even if the employer's phone, tablet, laptop etc, in many countries.
So what you're saying is that networked computers, user account management,.. hell, even HR are just plain illegal, because they know where you are? And don't get me started on aircrew... why, employers have special high-powered radio frequency devices that reveal their exact location every half second! Something must be done about this shocking state of affairs...
(And that's why you don't get legal advice from commentards)