A social worker shall not engage in, or attempt to engage in, any social relationship with a client or prospective client, or with any third person whom that client or prospective client knows, if a reasonably prudent social worker, in light of all of the relevant facts and circumstances, would conclude that that relationship is likely to result in exploitation of, or identifiable physical or emotional harm to, that present or prospective client.
258 CMR, § 20.07