In a similar manner to the way we determined that eating roadkill is bad without actually trying it ourselves or finding a case where someone else tried it, a person who is an expert on legal proceedings and court cases work would likely be able to determine the wisdom of a particular course of action based on his experience even though he might not know of a case that exactly matches the case we're interested in.
In fact, that's exactly what has been done for us by a man who specializes in analyzing the legal implications and outcomes of various types of shootings. Just as we were able to determine (by using some basic logical skills and our knowledge) that eating roadkill is probably bad for us without actually finding a case where someone got sick from eating roadkill, he has been able to make the assessment (using his experience and knowledge in conjunction with some basic logical skills) that using NFA weapons in self-defense could have some negative repercussions.
And I have had this exact conversation with this man, if it is who I suspect.
His response was 'My Momma didn't raise me to be a test case." He believes that since there is no case law regarding this that it is fair game to a jury, and who knows what will happen. Like him, I don't want to be the test case.
The point of this thread is moot
Actually those of us that actually own NFA items feel that this is a subject that deserves discussion. It is a topic that has been thought about by quite a few of us.
It was discussed here a while back. I wish I had been better prepared and written a better response back then.