A and C as an employer you will be facing a challenging minefield.
Having a robust policy like our EG801 helps in protecting both employer and employee. It does help if employees are encouraged to actually read and understand the policy.
Technological advances have been so rapid both the law and social netiquette have struggled to keep up.
Only this week four (now former) judges have been in the spotlight for using office computers to view pornographic material.
Three judges removed and a fourth resigns for viewing pornography at work | Law | The Guardian
I only use my company devices for company business and my own devices for personal use.
Simples.