The past mistake will not repeat it self as people have fully understood that they cannot afford to leave their future in the hand of miners who are self center of what benefit them only. At the moment am not planning to sell any of my Bitcoin for any fiat currency because I'm optimistic that Bitcoin will rise and not any serious will happen after the Fork in November. If you are afraid and don't know what to do convert some of your Bitcoin to altcoins, save other in exchange company and safe some in an offline wallet.