10% is massive regarless, but of what? 10% of messages being false positive flags would mean almost everyone getting flagged within a day.

Upsetting statistic for other reasons: Even if it's "10% of all flags are false, 90% are correct", if there's also no false negatives, then the 10% false positives alone gets you to about the current total incarceration rate — offenders are estimated to be a few % of the population, prison population is about 0.1% of the total population.

10% of messages flagged, which ought to be a minuscule number given nothing other than the sheer volume of messages.