Prabhupada has warned us not to go to or listen to professional Bhagavatam reciters. This also applies to devotees in Krishna Conscious. Because one who is not in the thought process of previous acharyas may definitely differ in his views and opinions and provide solutions in his own manner which I am not sure whether it is helpful for anyone who wants to understand and follow the parampara system of vedic education.
Also in a purport of one of the shlokas of Bhagavad Gita As It Is, Prabhupada mentions that one should not donate indiscriminately. (ISKCON always issues receipts).
How to recognize and stay away from the above types of people ?
Prabhupada says in one of his lectures:
Who is Guru ?
It is that who is a servant of God, it is that who follows the orders of his master.
You don't need a long definition about who is a Guru.
Besides this, in one of Prabhupada's interviews at Melbourne, Prabhupada tells us that one who wants to accept a Guru has to first find out whether the person is "fit" to be a Guru, (very important). "Knowledge of God" is second thing mentioned.