I would also say the employee should have covered up to the customer - told them there was no black pudding left but they could have double bacon or something instead. Then it would have been a none story.
It's also puzzling why the JW would refuse to "make" (ie fry or grill , as the pudding would come pre-packed ) the black pudding but be happy to serve it. What's the difference ,exactly between grilling something and serving it? - it is still a means of transmitting blood to the purchaser. The Society , in its hugely complicated talmud of rules & regulations surrounding blood and blood products allows a nurse or doctor to administer a blood transfusion , if requested , which is surely a much more direct form of transmission.