Facebook users can flag a video at any time for content they believe violates the website's policies, including during a livestream. Additionally, public livestreams with a large audience are automatically monitored by Faceboook reviewers, watching in case its content prompts them to cut it off mid-stream. A Facebook spokesperson told Popular Science that just one flag alerts a reviewer, who watches the video and decides if it violates the site's Community Standards. If the video remains, but is reported again, it is reviewed again; if reports continue, employees eventually make a decision about the video and stop reviewing it. If an explicit or violent video is left up, reviewers can choose to mark it with a graphic content warning, which stops autoplay and prevents viewers under 18 from watching it.