interesting. It is popular in the tween/teen age range so I guess they're just capitalizing on that.
I usually go to a JCPenney salon, adult cut is $30 and I have never paid extra for the flat iron.
Heck, I actually dislike my hair flat-ironed, so I'd be majorly irked if I had to pay extra! (I just let the stylist do whatever, and apparently flat ironing was popular, so it happened a lot... I think it was a cop out because I already have very straight hair!)
Of course I was also surprised to see the $6 charge to cut bangs on that list too. I've always gotten it done for free when I had bangs (plus tip). Guess that's how it works at the more budget model salons?