I think that what londubh proposed is a possible way to go. When presenting "difficult" information, doing so in a way that does not cause anyone to "lost face" makes it more likely that the information will actually be heard. Of course, a great deal depends on the non-verbal and tone of voice communication as well. And the owners do need this information, for not everyone will be as brave as you, to go and actually tell them WHY you won't be returning. And surely, there are others who are bothered by it, I know I would be...