Awhile back, I read an article in a Connecticut paper that said the state had decided to handle the non-compliance by attrition instead of attack. That is, if/when a non-compliant citizen rang for help, they'd be told help cannot be sent unless they were willing to comply with the law and turn over their illegal weapons. I'll see if I can locate the article.
I haven't found the article in question, but I did find two that're quite illuminating:
The “Assault Weapon” Rebellion
Connecticut halts plans to round up firearms after finding most cops in the state are on the list
Callthecops.net is a satire spoof site
Also on it: http://www.callthecops.net/all-us-ambulances-ordered-out-of-service-due-to-raciest-design/
I think we'd have heard of it