Well, to start it off, my in-laws ARE my landlords. There's nothing in the lease saying we -can't- have a homebirth, but considering their stance on my DS birthing center birth, I doubt they'd be thrilled with the fact we're planning a homebirth with baby #3(whenever that happens).
Besides the meddling in-law thing, do they have any pull on saying "no" to a homebirth? I've looked over the lease with a fine tooth comb, and there's no mention of water furniture(which would exclude a birth tub) and obviously, no one thinks of saying DO NOT BIRTH HERE in the lease. I don't really want to hide the homebirth, but don't plan on really talking about it either(they didn't know about the birth center until after the fact).
No legally they can't prevent you from birthing at home. I suppose they could call CPS or something if they wanted to be really evil but whether CPS would even follow up depends on your state.
I'd personally keep it a secret. Negative energy is never worth it :(