I don’t think you have much to worry about but IF they did do this there would be little you could do about it. Executive order freezing all IRAs, 401s, defined benefit plans. Work out the details after that while you (all of us) wondered why we didn’t see it coming. I do think that would be the last straw for a bunch of people who scrimped and saved over a life time for a comfortable retirement. The gauntlet would be thrown down.
Lots of bluster on here, but the reality is this stuff is 99% held in electronic accounts that could be frozen without warning.
And then what happens? Do you go over and shoot your neighbor who’s a janitor at the local federal building?
They can't freeze flying lead. And there'd be plenty of that.