For whatever reason on my iPhone (on the latest version of iOS, hasn't been fixed in 12 months even after a restore) whenever you swipe down on an iMessage in a notification, the popup always has the "report spam" box whether or not I have the contact in my phone (which is supposed to mean that they aren't spam). I've definitely accidentally pressed it before on people I know, I suppose since they still send me messages they haven't been blacklisted.
