Well, I did have a buddy who broke his Falcon in the middle of the down tube and it was completely chromed. In my experience, most frame failures, outside of abuse, involve chrome plating. Hydrogen embrittlement can be relieved by baking but it's a bit of a black art. There's disagreement over the temperature, duration and how quickly it should be implemented after plating. I was involved in Quality Engineering for some military contracts and even the military specs weren't convinced it completely alleviated the problem. It's just the sort of thing that can cause serious batch problems in a poorly controlled manufacturing environment. Given the amount of chrome plating on vintage bicycles and the differences in opinion over the baking control, I 'd be surprised if there was a vintage brand that hadn't experienced hydrogen embrittlement failures.