If someone is holding a bitcoin in a banned country, the punishment depends on what rules that country has. When a bitcoin is banned in a country, it doesnt necessarily mean that the holder of it will go to jail if proven, it means a holder cannot use these coins for payment or transaction because they are not allowed to. But if one has a bitcoin, I dont think we need to worry about it even if we are in a country that bans it because our identity is hidden and anonymous.