How to protect the project from fraud + your opinion is interesting?

Question

IT education

Good night, Toaster :)
It is supposed to implement a project to teach people certain things (IT) online. The project consists of two parts: the first part is free public access video clips (on the project website; watch as much as you want model). The second part is a closed group for students on a paid (monthly) basis, in the "one to two hours every day" mode. There is also a small third part, smoothly arising from the second - individual lessons with a person, also on a paid basis (per lesson or per month is not important yet).
The essence of the question is this - because the project needs to be promoted, it was decided to use the referral system, thinking about which I got stuck in a certain impasse. The clubbing does not threaten me, tk. there is nothing in the private part of the project that could be stolen. But at the moment it is not entirely clear how it would be better to implement the verification of new clients / students / project members attracted by the user? Provided, for example, such a model - "bring five friends, get a month of training in a group."
SMS verification is easy to fake (they took a phone from a friend and voila, there are 4 phones left to find). Verification according to the document also disappears, for two reasons - firstly, a request to Google, and here's someone else's passport for you. Secondly, some may become paranoid, they will not want their documents for some project (me) to shine.
What's the best way to do it?
PS Target audience: schoolchildren and students, as well as everyone who would like to improve their horizons (and not only) in the field of IT. A lot of interesting things are supposed, chewed as much as possible (the audience, we will assume, is “zero”).
What do you think?
I would appreciate your questions, thoughts and comments. Thank you!

Answer 1

1) If you want "iron protection", then as the desired result, you should take into account not the friends brought, but the number of paid training in a group or individual lessons. When the referred person has paid, the person who recommended the service receives the same amount on his account.
In the West, many people use just such a scheme, since it automatically rejects options in which users themselves register from other addresses, ask friends who do not need the service, etc. For example, Slack's affiliate program works according to this scheme .
If you take the classic options (like what you described above), then they are not without flaws. Users will find a way to cheat. However, if you wish, you can close your eyes to this, since in any case there will be benefits from such an affiliate program.
2) The audience is quite problematic. Make sure that your target audience is ready to pay for such classes. Maybe it makes sense to focus on older people who also have "zero" knowledge, but want to become a pro in some area.