And when a customer who might not be aware of the exact terms and conditions (there's quite a long list - I was actually surprised the first time I read through it) and finds that their request gets denied when such a guarantee was advertised so well (I've heard FAs announce this guarantee multiple times in a flight as well), it inevitably results in frustration for the customer. Not only did the customer not get compensation - the customer also wasted precious time talking to customer service.