That is simply untrue TommyC....how skeptical.
I can fully appreciate that some people who use the tarot may not have the mental stability to read from the cards accurately, and therefore may come to the conclusion that they are 'in danger'.
Actually, my advice to everyone is give it a go.....I support the belief of the majority of tarot card users - the tarot is not a way of communicating or attracting spiritual forces of ANY kind.
I believe they are controlled by the universe, and that with practise, anyone can use the cards as a valuable part of everyday life.
I agree with apricot and paul - tarot is down to the individual, and i think the complex human mind is more capable of bringing about things then we are aware of. If you go into the tarot with a negative opinion, believing that you're going to have bad luck, then you'll no doubt start experiencing bad luck, as you'll begin to interpret the norn as results of luck!!
(With regard to your question, it doesn't matter how the cards are shuffled, if you shuffle the cards, you re-align the 'universe' and set the cards for an unbiased and accurate reading. If you do not shuffle the cards, then you run the risk of 'influencing' the cards with your own thoughts, rather then the unbiased reasoning of the universe - i actually find this useful when i want to work out my own opinion on situations - give it a go if your unsure of your own feelings, don't shuffle and see what you get.)