I put 'answer' in quotes because what the President announced today really answers nothing. There is this weird meme floating about that gun shows are some sort of magical land where all the rules are different and those who believe this think Obama has done something to change it back to reality. He didn't, largely because gun shows operate just like the rest of the real world.
If someone buys a gun from someone who is not a federal firearms licensee (FFL), there is no requirement to perform a BGC as long as both of those people are residents of the same state and are IN that state at time of sale. In all other cases, a BGC is required by federal law. ALL other cases, period. At a store, in a garage, behind the cathedral at dawn, or at a gun show; it doesn't matter where, and it doesn't matter when. Virtually NO ONE who sets up a (gun sales) table at a gun show is NOT a FFL. Now for the logic problem: what percentage of gun sales at a gun show will NOT be accompanied by a BGC? Answer: virtually none.
It is possible that Jed will walk the aisles with a cardboard sign around his neck saying "Colt .44 Magnum; make offer" and it is possible that someone will make him an offer that he accepts, and a gun will be sold without a BGC. This will happen rarely, and what Obama announced today will not stop it because he didn't do what many in the Second Amendment Community suspected he might: declare that everyone who sells a gun is automatically "a dealer". Why didn't he do that?
Back in the 80s and 90s it was fairly easy to become a FFL. File the paperwork, pay a nominal fee, suffer a BGC that's somewhat more elaborate than the BGC for buying a gun or getting a concealed weapons license (CWL). Presto, change-o, you're a dealer. You can now buy at wholesale but you have to keep meticulous records of what you buy, what you sell, and from whom and to whom. All your sales then require a BGC and a 4473 which ATF must (by law) process and destroy in 72 hours. You keep your copies of the 4473s for 20 years before you can destroy them.
Damn, that sounds like the kind of Action Demanded by those Moms, doesn't it? Yes and no. They would take exception to the 'proliferation of gun dealers operating out of garages and living rooms', and that is why, in the 90s, Bill Clinton directed ATF to clamp down on 'kitchen table dealers'. If you didn't have a real place-of-business and only made occasional sales and purchases, they said, you're not a real dealer and just revoked your FFL. It would be difficult for Obama to have to admit that Bill Clinton screwed up, even if he did.
ATF (short for 'Bureau of Alcohol, Tobacco, Firearms, and Explosives') now considers a person 'a dealer' if they regularly buy and sell firearms and make a profit doing so, even if they don't have a real place-of-business, so Obama announcing that from now on ATF will require such persons to register as dealers is nothing more than declaring — to the blare of trumpets — that current policy will henceforth be enforced as current policy. In short, it's all hot air.
Outside of the Second Amendment Community, none of this is common knowledge, so all those Obama cheerleaders will be confident that their man in DC has just struck a blow for common sense. I think it would be cruel to spoil their euphoria, don't you? So let's just not mention to them that nothing happened today, okay?