What the central bank tinkerers don't understand is that blocking the exits doesn't quell demand for alternative monies. It stimulates it. Every time you set up a chokepoint, a new person googles 'what is bitcoin?' (or 'ما هو البيتكوين؟').
https://pbs.twimg.com/media/GIGtH-wWgAAIFVc?format=jpg&name=large