Good point. Though that's the difference between a Sporting Goods store with a gun counter versus a dedicated gun store. When most of your stock isn't guns you don't want to look like a vault and block your retail windows. In a perfect world locking the door would be enough, and store owners, no less than any other people, shouldn't have to structure their lives around the risk of bad people doing bad things.

Unfortunately "teaching robbers not to rob" is no more realistic a response than with any other kind of criminal. Precautions have to be taken.