NEVER? if I personally lost 15 fish in a row from a LFS...THEY would have a problemI would never blame a LFS for 15 dead purchases unless the LFS was putting them in my tank and caring for it. He can't take responsibility for what happens to the animals after they leave his store.
...but that's due to the fact that with all my years and experience in the hobby, and it's possible I could make a mistake, I know that it wouldn't be my fault 15 times!
Not to mention, I've seen plenty of LFS that do not know (or care) how to care for their fish, including proper acclimation into their own tanks!
IE: a LFS in my area, that makes a FORTUNE on the maintenance...has it's in store employees 'dump' new fish AND the shipping water, directly into their display tanks! When asked about it, the owner said that with all the copper and chemicals in his system, it's not a problem!
With that and the fact that he wants over $100 for a $35 Flame angel...I have not made a fish/coral purchase there in 15 years...despite the fact, that he rents his store from a family member of mine!
*FWIW I probably would have stopped buying from them after the 2nd or 3rd death...