Give it 10-20 years and you won't need to sign up, you'll just receive your UBI into your bank account every week. Well, that or the country you live in will have to let 30-40% of its people starve because there's nothing they can do better than a machine.

Remember, those idle workers aren't being paid a nice pay packet. They'll be on subsistence wages only. You'll still want to work a job if you want nice things.

If I'm one of those skilled workers who can do something better than a machine it seems the rational course of action is to move to one of the places where they let people starve and keep more of the fruits of my labor.

Until those people decide they should forcefully separate your head from your neck. See France (1787), Haiti (1791), USA (1861), Turkey(1908), Russia (1917), China (1949)...

Those are only the most notable major civil wars, but it's amazing how revolts are common across the world.

https://en.wikipedia.org/wiki/List_of_revolutions_and_rebell...