Maybe you are right. And to tell the true your are right. The high prices at Poloniex might became even because there don't work the deposits and the withdrawals. But how will explain you the same situation (level of prices) at Bittrex where everything work normally? The people may go there to sell/buy with the normal prices. And wait that the prices goes to their normal level at Poloniex and don't make activity there until that day.

Another thing. The activity at Poloniex (regarding hz) the last 24 hours is 3.65 bitcoin. There were the same amounts (plus/minus something) at least the last 3-4 days. Normally, before the beginning of the increase, the activity was barely 0.3-0.5 bitcoin. How is possible to name as obligated all this activity in such amounts when it is possible to enter only Bitcoin and not Horizon? Maybe is work of speculators which buy and sell within Poloniex with the same amount of money but there were not to many pump and dump of the price. Se even those has difficulties to do their normal actions to earn. So, why this big activity according to you? Normally, without the possibility to enter hz at Poloniex, the activity must be even less than before. So less than 0.3-0.4 bitcoin. Because there is lack of activity regarding the enter of horizon.