[Zeke]

In the U.S., at least here in CA, contractors must carry a bond. This is exactly the situation why. The bond company would pay to have the railings brought to code so you could have your final.

I can't advise you on the statute of limitations, but do look into your laws and see if there is a bonding company or completed operations insurance. The CO ins might be liable for work not done correctly within a time frame.

BTW, if the violation is simply too wide of spacing on the pickets, that's easy to fix with some heavy wire mesh.