Section 8 (e) of the current version of Form 4473 reads as follows:
"Are you the unlawful user of, or addicted to, marijuana, or any depressant, stimulant, or narcotic drug, or any other controlled substance?"
The 5th Circuit Court of Appeal held, in the Emerson ruling, that the bold print paragraph (the "I affirm that the foregoing responses are true..." language) which precedes the signature portion of the 4473 was sufficient to put Emerson on notice regarding the possession of firearms.
Even if all but one of the firearms pre-dated the current version of the 4473, they can argue that since he was put on notice regarding one, he was on notice concerning all.
Just enforcing the laws on the books, right? Too bad nobody mentioned a plan to get rid of the egregious laws first.