Ironic to mention then, given that Time Team's efforts were largely aimed at getting less well established sites rated as worthy of being scheduled ancient monuments...
...to protect them from the likes of treasure hunters (a.k.a. archaeological-context-destroying operatives) like your FB pal.
When they work -with- archaeologists, detectorists are highly useful, so I don't like to hear them being knocked in an offhand way but freebooting treasure hunters? No, thanks.