You think if government wants to seize it they can. This is your mistake. Government ALWAYS want to enslave. The reason why they don't is because their power is limited. Government is just another mafia. You don't fear every criminal organization do you? Yes they can kill you. Yes there is a risk. There are always risk.
Now I am not suggesting that you should evade tax or whatever. However, if your issue is fear, remember this. There are far more things worth fearing more. Within our life time, so many will evade tax that government will be forced to lower tax for everyone to reduce incentive of evading. Nowadays, google only pay 2% income tax. That's legal. Governments give up.
If I want to be blunt, most murderers get away anyway.
Cyprus government can't stop bitcoins. What makes you think US government can? The arab, the chinese, they are sick of being dominated by US government. Soon, they too will use bitcoins instead of oils to trade. People is sick of government.
So they have to report. So what? It's only the case once when you buy and sell that to dollar. Once in bitcoin it's hard to track.
Things go wrong if you get caught. Well, I used to be scared. Then I see how almost everything is illegal anyway there is little point in fearing anymore.
Recently in Indonesia somebody goes to jail for selling iPad without indonesian's language instruction. He is accused of comitting fraud against consumer, that don't feel being frauded at all.
Corruption run deep. When somebody bribe cops $20 and put the video on youtube, cops want to capture that one guy for "bribing". Every body knows it's common to bribe cops. What's not common is somebody putting it on youtube. Recently some people get killed for being ahmadiyah member. Cops do nothing. [ame="http://www.youtube.com/watch?v=UgY6N6Qe5EA"]Anti-Ahmadiyah Violence in Cikeusik - YouTube[/ame]
Why fear government if so many thing can harm you far more cruely and far more likely? You can get rob on the bus and nobody, not even police, will bother helping you.
http://www.firearmsandliberty.com/kasler-protection.html
Google cops obligation to protect and you'll see a long legal tradition that nobody has obligation to protect you, including cops.
Now you want to obey the law by not owning your own gun. Remember what happened to jews when they were obeying gun laws. Many kids in unsafe neighborhood will be better of buying gun legally and protect themselves even if it means risking jail time for gun violation. The alternative is risking being shot to death.
In US, somebody got 8 years for importing lobster on clear plastic bag. Only less than 1% of the lobster imported is "underage". Yet his millions of dollars of lobster is confiscated and he got 8 years in the slam.
http://www.talkleft.com/story/2004/01/06/181/65493/crimepolicy/The-Lobster-Police
Harmless things, like ganja is illegal. It's just a matter of time before government control anything we wants to eat.