bulgie
Dirt Disciple
That booklet doesn't say hydrogen embrittlement is the reason. They do say to "stove" (bake) the frame after chroming to eliminate any problems, which is the standard advice for hydrogen embrittlement -- heating drives the hydrogen out.
The specific reasons they state for not chroming are the possibility of thinning the tube during polishing, and the corrosion problems that can occur while chroming, or afterward if the acid isn't thoroughly neutralized and rinsed out. Those are the same factors for any frame, just worse for the thinnest stuff.
So I guess it can be OK if your polisher and/or plater are really good at their job. On the best chrome jobs I've seen, the framebuilder did the polishing himself, because the guy at the plating shop is used to polishing car bumpers and such. They might not grok how dang picky we are about our scary-light frames.
I assume everyone here knows, neither nickel nor chromium plating hides anything to speak of, so it should be fully polished as shiny as you want the finished product, before any plating.
Yes they can fill with copper, but that adds weight and rounds off the nice sharp lug edges that FBs are so proud of.
