Exchanges will earn their cut in IEO and investor will be still in risk . There is no guarantee that IEO cannot fail or cheat on later stage.
Did not see the exchange listing the scam/worthless coins first and delisting at later stages?
There is actually already people who cheat , as there is maximum you can buy with one account . Lets say your 5 friends create account on binance . Then there is IEO happening and you and your friends buy in , then you pay your friends lets say 10$ + investment money . After IEO they transfer tokens to you . Its called IEO Farming =D Imagine if you have alot of money and do it with 100-200 accounts , you can buy quite load cirkulating supply out like that