Privacy and security in the escort industry

I always thought that privacy was the standard in the escort industry. But recently, an acquaintance told me that a friend of his had experienced a leak of personal data after using the services of an unverified agency. It's not a pleasant situation, especially if you are a public person. I haven't used such services myself, but I wondered: what kind of security guarantees are there? How can you understand that the service really cares about the privacy of its clients?