Ref the NFA case, a good piece on "We have questions and

you have to provide answers.  HAVE to.  So do it."

I guarantee you there are gun bigots- almost all leftists- who would love to tell ATF to jail anybody who follows the court order; I also guarantee the ATF, even the "I don't like not having this power" types, who have some understanding of the shitstorm that would hit them if they did.  So it's for their own protection as well as that of average citizens that this is demanded.