How come these types of mistakes never happen to me?

An avreich in Bnei Braq wanted to move. he sold his house and decided to invest the money, 1.5 million shekels, in a safe stock while he looked for a new place to buy. According to Kikar, he told the bank clerk to invest the money in stock of Sony. The bank teller made a mistake and heard Coney, some sort of high risk investment in a company dealing with race horses.

The avreich comes forward "a few years later" to get his money (I guess to to buy his new house), he was shocked to discover that he had 7 million shekels in his account. He spoke to the bank and figured out what happened, that the clerk had mistakenly invested his money in this high risk, high return investment.

He then asked hsi rav if he needs to split the earnings with the clerk. The rav's answer was that he does not. I don't even know what the basis for the question is.

Again, how come these types of mistakes never happen to me...