It's already beginning to happen. Denmark has -ve interest rates and France has banned cash transactions in excess of €1000 as of this month. Italy already has such a ban in place. It's the thin end of the wedge.
Such a move, carried to its logical conclusion, harms those who are being self-reliant in putting cash away for their later years and forces them to rely on institutional forms of investment instead, such as pensions and other paper assets. Precious metals are still an option. Until the physical holding of these becomes illegal also.
IMHO, this trend reinforces the Prepper's need to:
1. Reduce reliance on money and the financial system by becoming more self-sufficient in basic needs
2. Invest spare cash in tools and learning skills so that one has a tradeable skill and/or the ability to engage in small-scale cottage manufacturing of essential goods.
The title of this thread was "One to Watch". It's certainly one I'm watching very carefully, although I accept that we are probably a while away from it becoming a problem for the individual. But, putting in place mitigation strategies in the event it does becoame a reality, also takes a while!
A little closer to home, from last year:
http://www.bbc.co.uk/news/business-25861717
"HSBC Imposes Restrictions on Large Cash Withdrawals"
In the end they blinked on this one, but it shows the general trajectory of thinking.
Find a resilient place and way to live, then sit back and watch a momentous period in history unfold.