When Temporary accounts rolls out, making an edit as an anonymous user will grant you a temporary user account, which you can then use to make more edits. Temporary users can be harassed just like full account users, so it might make sense to allow temporary user accounts to submit reports as well.
But for now, we do not want to enable temporary accounts to submit reports, to limit potential for abusing the system. We currently deny temporary accounts at the end of ReportHandler::validateUserCanSubmitReport by checking ot see if the user has a confirmed email. But we should change the !$user->isRegistered() check at the beginning to look for !$user->isNamed()