Most archeological sites (besides the ones discovered while digging holes on construction sites of course) are found by enthusiastic hobby searchers. In Germany interested people, mostly retired teachers of course, work as "ehrenamtlicher bodendenkmalspfleger", you might translate it as "amateur keeper of historical sites". Typically they regularly take a stroll through the fields and look out for remnants brought up by the farmer's ploughs, not only looking for new ones but also controlling if known ones are in danger of destruction. They are important helpers for the communal archeologists. They are also of course amassing a lot of knowledge in local history and it is allways amazing what they can tell you about the landsscape you believed to know. Of course this is also a way to channel potential pot hunters' activities into archeological support...