thats sad those fish are in those conditions. hopefully the owners are doing a lot of water changes. while i disagree that the owners "should be shot", i do think they need more education in fish keeping. maybe printing out some info for them and introducing them to the real demands and limitations of their setup could help. if they ignore your concerns, it would then be more appropriate to explain to them that any respected fish keeper would look down on their business and their handling of animals.
we can all easily blame people for their setups, but until you know more about the individuals and how much education they've had in the matter- its simply a waste of time to start judging. first find out if they're willing to learn and change- rather than bashing misinformed aquaria enthusiasts.