I see plenty of Bittrex investors buying on Poloniex at sub-ITO price, then selling an equivalent amount of their captive BLOCK into the Bittrex buywall. Cross-exchange arbitrage.
I believe deposits and withdrawals are closed during this 48 hour so you can't arbitrage.
what he means is, they buy the same amount of btc on polo as they did on trex and then get rid of their trex stach and keep the polo stach