So while these measures won't stop extreme communities from sharing objectionable material—and, yes, as somebody who has spent a lot of time with teenagers, it is difficult, as Mr Seymour said, to keep up with which dark place they may go to. For our tech-savvy teenagers, it's not going to stop them from seeking it out, but it can stop people from being inadvertently exposed to it—innocent bystanders traumatised, victims re-traumatised. 