Night before last UNIT went up to 0.06 on Cryptopia, is was 0.00006 (guesstimate) on Yobit, I had 100 coins that I could have moved to Cryptopia and made 6 BTC.
They both locked the wallets claiming they were under maintenance, and only opened the wallets once the coin had fallen down to 0.00005. And 1000's of us lost out on making some good money.
These exchanges control the market, they are no different to dodgy stock market investors, and there support ignores everything and the next day it is brushed under that carpet.