Justice Oliver Wendell Holmes who formulated the clear and present danger test for free speech cases.
There is no clear and present danger. If someone wants to a oppose the draft, he has a right to oppose the draft. Oliver Holmes is in the interest of tyranny rather than of liberty. The draft violates the 13th amendment, anyway.
The whole "OMG cheap guns for criminals" angle is pure FUD.
For now. Tech will get better, faster, cheaper, always.
... and it will still be FUD by definition to assume the worst of said technological development.
Sure, in the future it may lead to cheaper weapons for criminals, but conversely, it will also lead to cheaper weapons for the oppressed. So, unless you're a supporter of fascist totalitarianism, there is an obvious upside.
So feel free to try this at home, if you live in Denmark.
Really? I wonder what would happen if I sent Her Majesty, Margrethe II, a fake ricin letter...
Too bad I live in the (much to paranoid) US.