Some countries ban bitcoin because it is very fluctuating, and some think that bitcoin is same as gambling. There are also country think that bitcoin may endanger their legal currency. Many thought about it, but some day I believe that they will accept bitcoin as a part of technology-development.

It is definitely possible for you keep on trading using offshore trading platform, but maybe it will be more complicated to withdraw your money.
Every country has has their own financial law, depends on where you live, any legal implication? I'm not sure either.