The idea is drawn from things like structural engineers signing off bridges - where there's probably only one on a project, and if they won't sign off the design, neither will any other structural engineer.

I doubt it'll ever get adopted in the software industry, because we have many competent people doing good work without a software engineering degree, and degrees of low enough quality employers do whiteboard coding tests at interview, so there's not really a notion of a 'properly qualified' programmer.

Yes. If they designed something they knew was unsafe, or they were negligent in their design, or they misrepresented their competency I would expect them to be accountable for their actions as a professional electrical engineer.