It would have been damned difficult for them to find out about any guns I've bought privately from friends or relatives, or the guns I inherited from my father, grandfather, etc.
You ever bought ammo for them? On a credit card or bank card? Even at Walmart if you used cash there’s video of you going through the checkout line.
Ever talk about them on a phone to anyone? Via email? Any of your kin done this about family guns?
They gotcha if you have done any of this stuff.