Given Fast & Furious, how much of a restraint would you say that really is?
In terms of active FFL dealers, it's a pretty good restraint. If the ATF came into a gun store demanding to see the dealer's storehouse of 4473s, the FFL is going to scream to high heaven. I've never met an FFL who didn't absolutely loathe the BATFE.
Now, if you're talking about 4473s that have been turned over to the ATF because the FFL went out of business, they're still prohibited by federal law from accessing or reviewing the records. Do they obey the law? I don't know, but what good would it do them? Some of the records are 20 years old. (That's how long the FFL has to keep them.)