Yes, although, in many situations, it is also the ignorance of the store employee, instead of the self-interest for the sale. In the end, the consumer always needs to be educated, I agree.
If the store really wanted to make a "good sale," they could have taken Heli-Boy and said, "Well since you want a starfish, and chocolate chips are not reef safe, why not get a linckia/sand sifter/fromia/serpent?" The pet store would have just doubled to tripled their total revenue and got rid of an animal that they know should not be sitting around in their tanks for too long.