Mediums only tell you what you want to hear anyway. I could open a 900 line tomorrow, call myself a medium, and just say anything to whoever calls me up and make a fortune.
First - the medium conveys the information from the Spirit people around you. The medium is not personally interested in or involved in the content of the message. If the medium IS interested, then the message can get clouded by the medium and not received correctly or the message may be coming from the medium personally which can also lead to inaccuracies. If the medium is only "telling you what you want to hear" then you are being done a disservice. How can you tell? It's not that easy - through personal experience and the experiences of others.
Second - yes, unfortunately, you could open a 900 line and call yourself a medium. You don't have to be certified by any particular Spiritualist organization to call yourself a medium. As a result, you have plenty of good mediums who aren't certified, and you also have people who know absolutely nothing about mediumship but are claiming the title anyway. How do you tell the difference? It's not that easy - through personal experience and the personal experiences of others. Incidentally, you learn about your good mechanics, doctors, and lawyers the same way, regardless of their credentials (or lack of them).
As far as the psychic 900 lines themselves go, do people actually get good information from Spirit this way? Maybe. Is it an avenue that people can spend their whole paycheck on because they have made themselves dependent on readings for their every decision? Unfortunately. Is it right to be dependent on readings for every little thing that comes up in your life? NO. What's the difference between psychics and mediums? In order to appreciate the answer, you need more background, which you can find in my free book, Spiritualist Basics.
Third - yes, unfortunately, you could "just say anything" to whoever calls. Will you make a fortune? Maybe. It's your conscience, not mine. Yes, you could set up a business with a 900 line and lie to people all day and probably make money at it. For your sake, I hope that none of them jump off a bridge because of something you told them. Genuine mediums take that kind of responsibility every time they give someone a message or a reading. And it is a BIG responsibility. Genuine mediums practice mediumship for a positive good, and part of that involves being honest and taking responsibility. If you decide that you want to lie, cheat, and make money off the suggestible, that's up to you. Natural Law, however, has a way of handling repercussions that come from both good and not-so-good acts. Natural Law is also covered in my free book, Spiritualist Basics.
You are full of baloney - Spirit people don't exist, mediumship is a bunch of superstition, and when you die you die and that's it. Besides, you don't have any proof.