If you want to find a flaw, you will find it, regardless of truth, accuracy or sworn statements. I have come across so many folks claiming to have "PROOF" that psychic mediums are "all" fakes. But when you read their testimony, you find a great deal of opinion, and an even larger amount of argumentative passionate conjecture. The end result tends to be "your proof is nothing more than you own opinion, and the only next step is a fist fight, or legal battle in court". Which again, ends in stale mate and perhaps a big hospital bill, and a few stitches. None of which circles around to the initial claim of - scam, or no scam- being technically declared yay or ney.
What does happen is the growing issue of dis trust in any system. Anyone's word becomes less valid, and truth becomes a fleeting theory. This is how Atheist tend to think, in my opinion. Even science becomes questionable in many areas of historical facts.
The only way to determine if a psychic is valid is to have the experience yourself. Then make your own choice. Now, that being said, there are SCAMMERS out there in DROVES! Ready to pounce on a naive layperson. And, no, their ethical standards are equal to any other criminal. You must follow your gut instincts, and be very protective of your cash flow. There are many things to watch for, but as time evolves so does the scammer. So, you need to behave almost like a police person for yourself. But, if you want your friends opinion, please get a friend who is unbiased, or you will be dealing with the opinion of an angry scam expert who only believes their own eyes 50% of the time.