Parenting Truth #48: There is no such thing as "child proof." There is only child resistant.
As soon as you think you have the house proofed for your child(ren) he/she will learn a new trick like standing, climbing, walking, running or plotting with a sibling to destroy your illusion of safety. Nothing is out of reach once a child learns to stack and climb. Anyone know where I can buy a Nerf house?