I remember seeing a pamphlet, years ago (at least 12), regarding someone who had davened at the kosel for a yeshua (marriage, I think) for a long time. His friend tried convincing him to go to Rashbi, but he wasn't interested, saying the kosel is surely the best place to daven. After quite some time, he gave in, and went to daven by Rashbi. He immediately had a yeshua.
The paper concluded (in Ivrit, but I don't remember the words), "We see that even when Hashem Himself doesn't give a yeshua, Rashbi has the power to give yeshuos!"
It was ernst, well, kefira.
The pitfalls need to be known. You cannot forget the True Source when you are involved with what are essentially segulos.