I guess my confusion comes in at why there is probable cause for an arrest in the case of an NFA weapon, and there isn't in the case of any other weapon, which you must also meet certain criteria to possess. I have a big problem with the poster who alleged that this was a "presumptively illegal" weapon to begin with. Not being versed in the specifics of the law, I asked several attorneys, including a PD, for their take on LEOs using this assertion to generate probable cause for a search. None of these legal professionals had ever even heard of the term, nor could they locate "presumptively illegal" in any legal database. In other words, it is complete crap, a facade that can be used to justify whatever search or investigation the officer feels like pursuing, and hoping that a judge will back him up later in court.
Sorry, but to me that is an abuse of your power. You are not serving the public interest, and you are not following the letter of the law. I agree with your assertion that there is no reason to handicap law enforcement from enforcing the law, but my argument is that there is no evidence to support that there is a violation of the law here, any more than there is prima facia evidence to support the theory that everyone at the range should be subject to the LEOs inquisition simply because they have a gun. I guess LEOs can make up any legal-ish term they want and get away with it, but that doesn't make it correct.
I don't disagree with the logic of anyone here, and Fiddle has done an excellent job of explaining the various stages of procedure, it is just that I disagree with the assertion that there is a crime being committed, or that the mere possession of an NFA weapon constitutes probable cause. There is no legal foundation for this, as these weapons are not illegal to possess, they are simply restricted to those who have paid the appropriate tax. You are essentially auditing my tax records on suspicion of what? Tax evasion? Sure, I get it, ME HAVE BADGE, YOU GO JAIL. Hope that shoe doesn't ever end up on the other foot gents.