If you just keep in mind that the nice people who are doing your hair are the same nice people who failed high school chemistry class and ultimately didn't make it in college, you'll avoid worrying about "stuff" like this.
How much did the fancy shampoo not containing the mysterious "sodium" cost, I wonder? It's my belief that if the shampoo doesn't explode while it's hanging out in your grocery basket, then it probably doesn't contain "sodium." It may, and probably does, contain sodium lauryl sulfate, as another more tactful poster pointed out, but so what? If you have oily hair, then I'm guessing you'll be sorry to do without that ingredient...
If my hair ever actually looked any better as a result of going to the salon, I might put up to listening to some moron with a pair of scissors in her hands yap about stuff she knows nothing about. But it never does. I give the personal "Top Idiot" prize to the stylist who claimed that my straight hair could be fixed with vitamins. No, you dummy, straight hair is genetic. It can be fixed with a perm -- with chemicals. It can't be fixed by taking a pill. Sheesh. But I'm sure she made a nice side income selling worthless pills to the desperate.