How do you stop clients from teaching your coaching to others rather than recommending you to coach them?

I would like to become a life coach. I have started by practicing on some friends and family with the model and helping them. My question is how do you stop people from telling everyone about the main model? I’m wondering if people will just pass the info along to each other rather than paying me for the information? Has this been a concern to you? Do you ask them not to do this? This is especially concerning with the people I’m helping for free. Do you ever feel like I should coach this person for free because they can’t afford it and they really need help? I can’t wait to hear from you !