The more money there is in bitcoin (i mean as the price of bitcoin goes up), the more motivations that there are for scammers to figure out ways to exploit various weaknesses in bitcoin (whether that is taking transactions off the blockchain or some other schemes to obtain the bitcoins of others).
You mean like all the ASIC companies and the thousands of miners who got robbed blind by pre-order scams? How about the half a billion dollars in coins Empty Gox made disappear? First Pirate Savings & Trust?