We should also keep in mind that in other nations, illegal metal detecting is even more rampant and damaging, as is the case in Bulgaria and other Balkan nations which are the primary suppliers for the indiscriminate trade in portable antiquities (ancient coins, fibulae, buckles, weapons, and other small metal finds).
Nighthawks and illegal metal detectorists around the world largely supply the voracious and unquestioning market, not those operating ethically within the Britain's PAS scheme.
For some news reports on nighthawking in Britain visit: D.W.J. Gill, "From an Illicit Hobby to a Semi-Professional Criminal Industry," Looting Matters (16 Feb. 2009).
See also a recent story posted to the Museum Security Network: "Bronze Age Axes found in Buckinghamshire Using Illegal Metal Detection Were Sold on Internet Auction Site eBay, English Heritage Warned Today" (16 Feb. 2009).
For some recent discussions here on Numismatics and Archaeology about looting in Bulgaria and the Balkans and its relationship to the indiscriminate trade in ancient coins and antiquities see:
"Italy Returns Thousands of Looted Coins to Bulgaria: Is there a Connection to Past Criminal Activities?"
The lecture, "The Trade in Ancient Coins in the USA: Scale and Structure" also addresses Bulgarian and Balkan sources.