Being a physics/science fan, I have read extensively the material on that site before.
It is quite interesting, from a science standpoint.
As for non-proliferation.. I think they key to that is the fissile material iteself.. once that is aquired, assembly of a crude device is not difficlut. (Not all that easy, there are some tricks even to the HEU "gun" design, like premature detonation, etc. But I think they key to non-proliferation is the fissile material.. that is the hardest to get a hold of, and that's where it should be stopped.
These designs don't mean a thing if you haven't any Plutonium or U-235, conversely, if you have Pu or U235, you could build a device without these designs.
Thank you for the info.
If it fizzled it would still go critical, irradiate a lot of people, contaminate a large area and cause economic chaos.