Things like that don't happen worldwide in sudden, There are laws and regulations in most of the advanced world and I guess BTC is still far from forming a threat that such movement come in place... I guess the community will still use it even if it is banned.
Well they will still use it because you can use bitcoin only in the internet so anytime you can deal in your house without going to outside.
For me if it is banned i can be still to use bitcoin since i am always online.. in my house..