My dad was up on a balcony three stories up, working on the sliding doors. Visitors let their 1 1/2 year old boy out for a little fresh air. Here’s what my dad told me: “I turned around to look to see what he was doing, and he had his head, and chest through between the post and the wall. Had I not quickly grabbed him, he would have walked right off the balcony”
The difference in width was perhaps only 5-7 cm, but that’s all it took to get a little boys head through the spindle and the wall. And why did this happen? Well, evidently, some installer that that close was close enough; and obviously no building inspector caught the same flaw.
Lesson here: The spacing between the end posts and wall, and between the spindles themselves are for the protection of children. We make sure you are safe.