I voted yes, but then when I read about the cyanide I would have said no. I know it's hard not to rescue the fish, but if they are buying nuked fish and we are buying from them, it only encourages the practice. If they die at the LFS, they take the loss and will eventually (hopefully) buy fish that are less at a risk for loss.
Having said that I have rescued fish from the LFS but didn't pay much for it, but spent a fortune at the vet getting it an antibiotic shot and antibiotics for treatment. I have also heard of a lady that rescues fish from some of her LFS, but they give them to her, she tries to save them, and then re-homes them if she can turn them around.