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?
Got milk? Got glass splinters and shards in your milk? In my childhood, we did, from commercially re-used glass milk bottles.