Facebook is tweaking its policies towards underage users, TechCrunch reports, and it will begin requiring those suspected of being younger than 13 years old to provide proof of their age. The move comes after a report from the UK's Channel 4, in which an undercover journalist began working as a Facebook content reviewer. Though Facebook and Instagram require users to be at least 13 years of age -- in order to comply with the US Child Online Privacy Protection Act -- the report revealed that in practice, those rules were often ignored. "We have to have an admission that the person is underage," a trainer told the reporter. "If not, we just pretend that we are blind and that we don't know what underage looks like."