Do these people ever think through what they are proposing?
First of all, banning something doesn't make it magically disappear.
Secondly, the logistics involved with confiscating every firearm in the country are too staggering to contemplate, both from a manpower standpoint, let alone the legal and moral issues. How many cops really want to go door-to-door taking away lawfully-purchased guns from angry citizens? That would be the definition of hazardous duty.
Of course it does. Laws banning guns are the only laws which criminal do obey! Doncha know anything? ;-)
Every citizen is considered guilty for not filing an income tax return and, unless each proves otherwise individually, all 300 million of them, he is assumed liable for the highest tax rate possible on all income, and assumed to have no deductions.
What could be more absurd and difficult to implement than that? Yet that is the law of the land, applied constantly, every day.