....same here in the South Bay. You can't even smile or talk to their kids without them grabing them and pulling them away.
It's a holdover from Moorish influence in Spain (I think--would be interested to hear if I'm wrong). One indication that it has Islamic tradition written on it is the wearing of bits of blue jewelry. In Islamic tradition, the color blue wards off the evil eye. That's why the burqua in Afghanistan was always blue, because women are so evil they need a charm against the devil.
Anyway, it's a very primitive thing. They probably also put eggs under their beds to absorb sickness. At least they have to pay their curanderos with cash, and it keeps them out of the ER.