My immediate family on my side (as in my mom and three aunts) are all very against homebirth and though they certainly would never call CPS on me, I still won't be telling them that i want a homebirth.
I don't think lying is the way to go though. Lies are have ugly energy and you'll also never know when the truth shall out, so it's better to avoid them. Not telling the whole truth and omitting details is another thing, though

What I'm planning to do is tell them that I'm seeing an a midwife as well an ob for prenatal care. Then I'll call them after the birth and if if was a homebirth I'd just tell them that I called my midwife who came over and checked me and stayed with us wile we birthed at home and that everything was safe and fine. At that point they couldn't say anything but that they personally won't have risked it and that I'm lucky that nothing went wrong, but I will have avoided any possible negativity and worrying on their part if they knew ahead of my plans.
But then, like I said, they would never call CPS on me, so perhaps my answer would be different if that were the case. Still, I don't think I would lie, I just wouldn't tell the whole truth and call them many hours/days after the birth when you feel up to talking to them/having them over.