Unintended consequence: MILLIONS of new NFA weapons-holders. And that makes us realize we can easily own full-auto as well.
There are several states which prohibit all but law enforcement (in the performance of their duties) from obtaining NFA licensing; in those states, if the AR, AK, etc. are deemed NFA weapons, they will have to be confiscated by state authorities. I don’t know if the courts (or even these states) would want to go with confiscation. I wonder what the ACLU’s position on that would be, since it would require a violation of the 4th, 5th, and 2nd Amendments. (I know the ACLU does not support the 2nd.)