I don’t think it is a discourse problem. However, this is definitely a problem with the users entering wrong information to get access. I would suggest a different approach here.
Set up something like a google form where users are required to answer the questions that you are asking them upfront. Let them fill in those answers and submit a response.
Review these responses manually and send a one-time invite link to your community to the user so they could sign up.
Now, make a check box on signup page asking for their consent that if you find the information that they provided is incorrect. You will ban them without warning.
This is a good way to tackle the situation in my opinion