>If demo was any good you would see such exercises all over the world on a regular basis.

I wonder if it's mostly a logistics reason they don't do it often. To do it smoothly, you've got to produce and safeguard a mountain of currency, with a high degree of secrecy, and deploy it in short order when the demonetization is activated.

It reminds me a lot of the 1962 replacement of the Hwan with the Won in South Korea. I get the impression this was a complete shock change (new Hwan notes were introduced less than a month prior to demonetization, and the replacements were produced abroad).

They pulled it off only with a fair bit of challenge-- old coins got forced back into circulation, and several type of the new notes were replaced almost immediately, and this was in a country which had a tiny population and economy compared to India.