alt Hacker NewsWith e2e encryption, the signals you have are pretty minimal.
Let's say a 40 y/o man finds a phone on the ground, sees a name stuck on it, googles "name + town" and finds the facebook of a 12 y/o girl, and messages "Hey I found this phone, do you recognize it? <photo>"
With e2e encryption, you can't easily tell the difference between that and a creep.
This thread is advocating that exactly that case should result in a police visit with the assumption of guilt.
The world is nuanced.
Imagine no e2e for a moment for FB. Policy can be smart enough to pick up that this communication is not represntative or normal. That's part of detection.
Second, a single message to someone on a random phone is not going to flag anything.
Third - there is no assumption of guilt. Not even an arrest is assumption of guilt.
Finally - those are extraordinary corner cases. They will happen, but the get resolved the moment the guy says 'oh, I found this phone' - because that will be 100% clear in that context.
Obviously - things can go awry. Meta flag something as bad, sends it to police - they do not follow procedure, or don't apply something correclty and arrest a guy at his place of work. But in the scenario you described, its literally not a problem - there are 'common sense checks' through the whole thing. The algo, the human making the notification to the police, the police, the judge if a warrant is required. People are not going to be arrested because they found a phone and texted their niece - if that happens, then we have another set of problems.
We can 100% have our 'friendly community' with Facebook.
Now - with an e2e thing like Signal, well, yes, it could theoretically be a problem, but the likelihood of some rando finding a phone, that's not locked, and being able to text some other 12 year old, an effectively 'pose' as their 'contact' - well that's a rare case scenario.