Adults with authority control the home, the school, and most activity spaces. Teens are told where to be, what to do and how to do it. Because teens feel a lack of control at home, many don't see it as their private space.Link
To them, private space is youth space and it is primarily found in the interstices of controlled space. These are the places where youth gather to hang out amongst friends and make public or controlled spaces their own. Bedrooms with closed doors, for example.
Adult public spaces are typically controlled spaces for teens. Their public space is where peers gather en masse; this is where presentation of self really matters. It may be viewable to adults, but it is really peers that matter.
Teens have increasingly less access to public space. Classic 1950s hang out locations like the roller rink and burger joint are disappearing while malls and 7/11s are banning teens unaccompanied by parents. Hanging out around the neighborhood or in the woods has been deemed unsafe for fear of predators, drug dealers and abductors. Teens who go home after school while their parents are still working are expected to stay home and teens are mostly allowed to only gather at friends' homes when their parents are present.