I dont see how they can enforce any of it considering so much of it infringes on the 2A. Even the 94 ban did but why it was not challenged to the point of over turning it is beyond me. Perhaps knowing it would end in 04 had something to do with it and maybe the severe back lash this time around has a lot to do with the internet and how we can all be connected around the country to know what is going on as far as 2A issues.
Bingo! If it wasn't for the 2004 "sunset", the law would have been doomed in the SCOTUS, and taken about 9 years to work it's way there. Just as you said: we are better connected now, we can coordinate efforts quicker, and there are a lot more lawyers looking for a big payday and/or to make themselves famous. And now, with D.C. v. Heller and McDonald v. Chicago, it makes the "smell" test in court a lot more difficult for any sort of national restrictions and bans. Both cases established that not only do these bans and restrictions affect our 2A rights, they affect our 14A rights, and any sort of ex post facto registration would be a violation of our 4 & 5A rights as well.