Local occupancy clauses on market housing - Public forum - Planning Advisory Service (PAS)

Hi, has anyone heard of any planning policies that restrict market housing to locals only? I am aware that national park authorities can do it, but I'm not sure how it's justifiable elsewhere. I gather Eden District Council's emerging policy HS2 is looking to restrict market housing to local connections in several settlements that are designated rural areas, but there's nothing in the Council's evidence base that seems to show how the policy was arrived at. Any experiences from elsewhere that could help me would be great. Thanks, Steve