@tim If I write a classifier to detect harassers and it decides to block 100 people and 95 of them are not harassers, those 95 people are false positives because you _also_ have the option of blocking exactly five people.
I'd view whether to call them "collateral damage" or "false positives" as more of a semantic debate: it's important, but it depends on how you define your classifier more than on the meat of the problem, if that makes sense.