It may be useful to alert Foster Carers to this, and/or to open up /have a discussion with young people directly.
Instagram is overhauling the way it works for teenagers, promising more “built-in protections” for young people and added controls and reassurance for parents.
The new “teen accounts” were introduced in the UK 17/9/24. They turn many privacy settings on by default for all under 18s, including making their content unviewable to people who don’t follow them, and making them actively approve all new followers.