If they already know, why do they bother asking?
Because "they" are already collecting/building gun owner databases for the future when the 2nd Amendment is gutted. They won't have to send LEO's to your door to collect your firearms, though. They will make a few special raids on high profile private citizens to shock and intimidate the sheep. For the rest, they'll just freeze your bank account, suspend your driver's license, deny you government medical care, etc., until you personally surrender your firearms at a designated collection point.