This was commercial milk delivery across a country, several millions of people.

"Proper rinsing" is not adequate for commercial operations. High temperature (near boiling) water at fairly high pressure, tens of thousands of bottles in a batch. Metal baskets, mechanical conveyors. I'll let you imagine the failure modes.

I lol'ed at the thought of milk bottles being rinsed by hand in a commercial operation. How much do you want your milk to cost?

Turned upside down on a conveyor, and having the insides and outsides blasted by high pressure caustic solution is rinsing properly. And exactly what I was referring to.

Glass shards aren’t going to be able to stay inside or on any bottle subjected to that.

But if a neighbor shattered at some point when later filled, it could happen I guess.

Though that would apply to anything bottled in glass, new or old glass yeah?