My point in this was that the FIRST GUY to get caught using one of these in a shotgun only area would be fine. If the law says "shotgun only," then legally, he's using a shotgun, and even though it might not fit the spirit of the law, it fits its letter. A state couldn't judge that first guy's shotgun to be a rifle - so he couldn't get in trouble.
Now, I'd fully agree with the premise that after catching the FIRST GUY, the state would compose a new regulation the next year that would prevent the SECOND GUY from using one.
Nobody would get in trouble - today - for using one of these in a shotgun only area, unless something else in the regs already exists to prohibit it - which is what Oldtimr and Superhunt proposed.