It is a one sided fight. You and I have to be vigilant whilst doing what we do in our lives. For the scammers, it is their job, often backed by an organisation providing an infrastructure. It gets wearing, and makes us a bit paranoid. In my case, both the home phone and mobile will block calls that are not in the contact list, (sending them directly to answerphone), although I get a notification of the time and number so I can review if I feel the urge. Just have to make sure the doctor and nurses mobiles are in the list, they tend to use mobiles rather than a desk phone.
Perhaps it is for manually reviewing items flagged as 'unsuitable' (understatement). For that job, the start point for negotiations would be £500
per hour.
It is probably standard operating practice to never target the country you are operating from. So zero it is.
Andrew.