That happens to me too with the grass thing. It's happened multiple times. And it's kind of creepy because sometimes, the giggles sounds like there's multiple kids, not just one.

And, honestly, this got my imagination to run away just a little bit. But it involves some spoilers about the note events...

We know from the notes that Margaret and Bill were having some issues and that at least some of these issues involved children. What if they had kids who died in the fire that destroyed the main room and we are hearing their ghosts and digging up their remains

I'm sure they would never make the game that macabre, but it could make for an interesting story.