As I'm sure that Squantos will agree, the key to success in any endeavor is not to do exactly as one's opponent expects. In the event of a hypothetical gun ban and subsequent confiscation, I'll bet that the assorted alphabet agencies expect that gun owners will mostly turn in their guns, and that the rest will stay home and wait to be burned out (which, as we all know, has moved well beyond exact science, and has been developed into something of an art form). What they aren't counting on is those who will likely be doing the exact opposite to those who give unconstitutional orders (note, this is NOT a recommendation, incitement to commit any act of violence or advice, only my personal opinion of what will happen).
One bit of optimism: even our sheep-like neighbors to the north haven't registered all of their guns, not be a long shot (pun intended). If Canada has massive non-compliance, I'll bet that the folks that we are speaking of have nightmares about what would happen in this country - and that's a GOOD thing, as it prevents that particular dream from becoming a reality.
And yes, I've reminded my Congress Critters a couple times already. Ball is in their court.