The problem is: I cannot find the link to this article anymore, because searches invariably turn up tons of positive articles that all use suspiciously similar wording - kind of as if somebody with an agenda was consciously working on copy&pasting similar texts all over the internet.
At its core, the idea underlying the Wörgl experiment is actually very simple and most likely true: When a monetarily sovereign government isn't afraid of spending, they can do good things.
You don't actually need an artificially value-losing currency for that, you just need the political will for spending.
There is no real economy backing Bitcoin.
At some point you need to convert BTC to real money for taxing and what not and this conversion is the perfect place to ban it if so desired.
Nice experiment currently backed up by blogging.
Look at what happened in the Worgl experiment - http://en.wikipedia.org/wiki/W%C3%B6rgl - once the idea gained traction the central bank outright banned it, so that other towns considering it, could not start up a competing currency.
Can Bitcoin be banned? Not without crushing the Internet; but if made illegal (or just subject to very onerous reporting requirements) such that businesses in the USA could not easily use it, it would stop Bitcoin's growth dead.