If the person is getting their job done while also using the internet facilities for other reasons and there is no clear policy stating that this is not allowed then telling to cop on might be dodgy from a disciplinary/employee relations point of view.
The new starter has no rights under unfair dismissals legislation, so there is no risk to the employer in this case. The employee deserves immediate direct feedback. I'm not suggesting firing them, or holding this against them - Just make it clear straight away that internet facilities are for business use only.
If the person is getting their job done while also using the internet facilities for other reasons and there is no clear policy stating that this is not allowed then telling to cop on might be dodgy from a disciplinary/employee relations point of view.
I wouldn't imagine so
If they were using a phone to make calls all day as well as getting their job done it would not be unusual to tell them to cop on