I do agree that such hard to keep fish such as powder blue's should not be sold to a beginner hobbyiest. However! I don't know how many reefers know that ordering fish is no simple task. It's all about availability.
Let's say your a store owner for example, and a customer begs you to order him/her a yellow tang. Maybe after a few weeks of being faxed availability list, you finally see yellow tangs on the list. So you order one for that patient customer and three more for stock. With most suppliers, it's sometimes luck of the draw if you get exactly what you ordered. So what happens if the supplier you faxed back your order too is all out of stock of yellow tangs now-well too late! Most times they will substitute powder blue or another type of tang for the yellow tangs, or manderian gobbies for yellow watchmen gobbies for another example-that's just the way it is!
We should not be so harsh on our LFS
as it's not there fault most of the time-it's the suppliers. That's why it's so hard for stores to find a really good supplier. If I was a store owner I would not want to order a whole bunch of fish that nobody wants to buy-but what happens when my supplier substitutes them by mistake or just wants to get them on his/her hands- then I'm stuck selling them at a sale price because that's all I can do. No, I can't send them back so I have to try and sell them. If you tell your supplier to stop sending you powder blues, then who nows, maybe you will never get sent another tang ever again or he might just add more to your next shippment. So what I'm saying is "it's really really hard for a LFS sometimes to have control over what they recieve in there shippments".
just my opinion, peace all
cheers, Rich