> Decades ago I read that at some point each feudal lord coined his own currency for his peasants. If a peasant escaped, he wouldn't have means to take anything with him.

A modern echo of this: Several times in the gloomy AM hours, I have worried what might happen if the current US administration tries to impose capital controls [0] like China. You might flee to Canada, only to find out that most/all of your life savings are forfeit to the tender mercies of the US government.

[0] https://www.reuters.com/markets/us/investors-could-exit-tari...