There's a Congressionally chartered organization called the National Center for Missing and Exploited Children that solves the problem of how to let the FBI inspect every Facebook photo. This model deserves more attention for contact/location tracing. https://www.washingtonpost.com/opinions/2020/04/16/be-very-wary-trumps-health-surveillance-plans/ …
They make thousands of law enforcement referrals a year. The feds consider them an essential partner