Explain whether it is fair for employers to judge Miguel based on his social media usage.

No, it will not be fair at all in judging any employee on the basis of his or her social media usage, until or unless that employee is interfering in any of the organisational domain in a negative way. Its the basic right of any worker that he can spend his private time in whatever way he or she likes. Social media has become one the important needs in the modern world today, if an employee is using social media for his private leisure time than it all depends on him or her BUT the usage of social media in the working hours should be seen carefully and the employee must restrict himself from it during his official working hours.