What is the threshold of scale when a private citizen has multiple homes? Can that individual collect biometrics from their visitors and do whatever, privately,

What is the threshold of scale when a private citizen has multiple homes? Can that individual collect biometrics from their visitors and do whatever, privately, with that data as long as they wish? What if that same individual owned one or more private companies? Can they collect biometrics for internal, private use, then? Even if that private individual is an internationalists, traveling to different countries with access to that data at will, perhaps with specialist staff analyzing that data?