HIPAA regulations are related to patient privacy and data security. Your use of headphones has nothing to do with either of these. They are responsible for securing their data systems from intrusion which may cause loss of data confidentiality, availability or integrity (CIA). If your use of a smart phone with headphones have any effect on their system's CIA, they have already failed, and you should let them know you'll report them to the HHS for an audit if they persist in their bs.