The problem isn't so much malicious abuse of red flag laws, but those who believe they are being responsible.
No inside knowledge as to the mental fitness, plans to commit violence, or even their fitness to own guns. They will simply report something that "doesn't look right" or "makes them nervous or afraid," and the authorities will take it from there.
Not everything is as people perceive it. There's much more risk of false positives than there is of prevented real violence.
As I said before, if you do turn someone in, and they don't commit a mass shooting, how can you ever know you were right? 100 red flags is not proof of intentions; Only the act is proof, and normally there are not enough flags to stop them -- or we get another Parkland High School where the authorities were all incompetent.
Will this catch anyone, or will it be a warning to anyone planning a violent event to watch their OPSEC, making it that much harder to identify them?