Don, great question. I made it very clear to everyone when I went vegetarian (or mostly vegetarian, as I was at first). I started this blog and told everyone about it. So if you use facebook or something like that, tell people there. (Although I guess your parents and in-laws aren’t likely on Facebook.) That’s a million times easier than showing up at their house and saying, “Oh by the way, I can’t eat what you’re making for me tonight.” As long as they know in advance, even if they don’t really respect it, people are usually understanding enough and not offended that I brought my own food or ate beforehand. At least that’s been my experience.