When I was a kid we played a game »Land Grab«. The game goes as follows: There are two opposite players. The playfield is on the ground divided in two halves. The first player would throw the stone on the opposite player's ground and then draw a new border around it with a stick; the new line represents the new borders of the player’s land mass property. Then the opposite player would do the same. If either one crosses the drawn line or touches the (yet the opponent's ) ground with hand or feet then the newly to be acquired land is lost. The winner is, of course, the player with the most land property.
It looks like this old game evolved on a whole new level this year.
Sweden has announced that they will put their whole land registry on the blockchain smart contract system to minimalize human error. The system is in testing phase and is to be implemented and operative in 2019. Also United Kingdom is considering the use of blockchain in this area, and for state realties Georgia, Russia already quite far in the development of this project. http://www.coindesk.com/sweden-blockchain-smart-contracts-land-registry/
They announced that the seller-buyer process in real estate business takes 2-5 days and with this it could be done within 5 hours, and quite some business of attorneys, notaries, and real estate agents could be lost.
As of just recently, I heard of the copy and paste virus (Pastejacking Malware https://news.bitcoin.com/bitcoins-price-rises-security/ ) that was regulating its own menace on the cryptocurrencies exchanges. The virus pasted the purchased or acquired amount of cryptocurrency into the virus/malware maker's account. Plain and simple. And, as in the blockchain transactions only the consensus counts not the person carrying out the transaction, the program doesn't care whether it is money sent to you or someone else.
I guess anyone who learns how to program in the appropriate coding language and is angry or malevolent enough can steal something out of this One World System in the making. Or maybe, the only thing such person needs is the conviction that he/she or some higher power has the right to do so. And there are many who’s minds are set in this direction. Combining such conviction and excellent knowledge of programming or just loads of money could be a deadly combination in this case. According to them it is like they are executing their God's commands (whoever that might be or even if it does not exist). And, whooosh, one day you just get a note that you don't own your tiny piece of land with a nice little house and maybe don't even live in your state of yesterday.
You might say, oh no, blockchain smart contracts are safe, nothing could happen. Well, maybe. We'll see.