Note that there is a lot of lobbying involved in the building code. An example:

What if a kid ran into a balcony glass and broke it, hurting or killing itself? Better demand that balcony glass be reinforced (and more expensive, to a great delight of the glass factories!) just in case. Even in old folks' homes.

No one wants to be known as the child killer, so here is a new demand making the construction a bit more expensive.

That seems perfectly reasonable to me. I expect balcony railings to be sturdy, they exist precisely to prevent accidents. As long as there is no regulation mandating railings be made of glass, I don't see any problem. I've only ever seen glass railings on the houses of people who can afford to pay someone else to clean them (i.e luxury housing) so I don't see how that makes it harder to build affordable housing.

I meant glass in the door that connects the room to the balcony. Not in railings. Sorry.

earthquakes, at least in SF