Safe Search: Virus = Scam Website?

There have been cases (another just happened today) where I have seen Safe Search flag a site as Caution or Unsafe, and then looking at the details I see that there are no threats listed except for the "virus" "Scam Website" one or more times.  In at least a couple of these cases there was no user feedback, which is where I assumed such a "scam" designation would originate.  Does Safe Search somehow identify what it suspects is a scam via automated site assessment?  Or does Norton have people who actually peruse the web and make assessments?  Or something else?