“...then they have a better ability to round up and confiscate.”
Who is “they?”
It won't be a dramatic roundup with the SWAT team in attendance. They will just pass a tax on firearms possession.
If you are on record as owning a firearm, then the tax will be assessed. It will start low. If you pay it, you acknowledge owning the firearm. If subsequently you refuse to pay it, then they put a lien on your house, and you won't be able to renew your drivers license until you pay. They will tell your employer to garnish your pay, and tell him why.
Eventually your wife will be fed up and turn them in while you're at work, just before she files for divorce.