"Witch's Balls and Bottle Trees keep evil spirits from coming into the house.
Sunlight shines through the colored glass, the spirit sees it
and flies into the bottle or ball to investigate.
Once lured inside, they cannot get out again"
Either that or you're so tipsy from drinking the contents of all those bottles, you simply don't notice the evil spirits floundering around the place.
I definitely see a bottle tree in my future...