A failure rate of only 50% is absurdly good for a system like this. If we have to:
> Imagine your phone scanning every conversation with your partner, your daughter, your therapist, and leaking it just because the word ‘love’ or ‘meet’ appears somewhere.
then apparently either there are so many perpetrators that regular conversations with partners etc. are about as common as crime, or such regular conversations don't have such a high risk of being reported after all.
I don't think chat surveillance is a good idea. But please use transparent and open communication. Don't manipulate us just like the enemy does.