If I were a prospective purchaser, I'd be filing an action for declaratory judgment and petition for restoration prospectively; If I'd already gotten into the transaction and been denied, I'd appeal the denial (get a lawyer, though, the reasons are legal and technical and will have to go up several levels and will end up being heard by a judge).
If I were a dealer, I would give the person who'd been denied a copy of the "how to appeal" brochure, tell them what happened and why, tell them to call their lawyer right away, and let them go. I would not hold them by telling them there'd been a delay. And, when the VSP arrives, I'd probably tell them they need a subpoena for the documents. But that's just me. I wouldn't advise anyone not to co-operate with law enforcement. I figure that, if the cops want to arrest them at their home, they've already got the information necessary to do that.
The reason I say all this is that they're going to want to charge the prospective purchaser with lying on the official form, a felony, and they could, in theory, charge him with federal offenses as well (though I've never heard of the VSP having done so). Keep in mind that all that's required for the arrest is probable cause, not proof of guilt. And a reasonably held, good faith belief that the arrest is appropriate is pretty much all that's required to relieve LEO's of civil liability under the affirmative defense called, "qualified immunity".
I'm looking into filing such a suit right now for someone; anyone else who's interested in joining in a declaratory judgment suit should call me or send me an email. The people I'd want to talk to would be people whose rights will be affected by the VSP's change of policy. The sooner we get on this and the more people involved, the better.
One more thing - people who purchased prior to the publication of Castleman were legal at that time. Whether they're lawfully in possession now is not a problem as long as they don't engaged in any acts involving actual "interstate commerce" - e.g., no trips with a rifle to W.Va. for hunting; no shipping guns to one's self in another state; no carrying guns in a vehicle under the Gun Owner's Protection Act. No buying or selling guns or ammo from a dealer or across state lines. Acts not involving interstate commerce, e.g., private in-state sales are not regulated by the Fed law and there is no state law prohibiting a person "convicted of a misdemeanor crime of domestic violence" from being in possession as far as I know.
