None are 100% accurate, not even the best of the best. I work in the industry and have my own abilities, I do not predict the future, I deal with the here and now.
Sadly, there are many, many fakes out there, there are also many con artists. NEVER give someone tons of money to do a spell, bring someone back to you, help you win the lottery, etc..
Anyone who is ethical will tell you that we all have the ability to be wrong, as we interpret message that often come in well for lack of a better word a bit in code.
Hmmm this might make a good hub LOL!
Just be careful, get references and if it doesn't feel right, trust your own gut first!