As an investor, i cannot participate in IEO conducted by small and new exchanges. The main reason why IEOs are preferred to ICOs is because they are more prone to scam than ICOs, and this is because the exchange validates its legality with their reputation. Imagine Binance or any top exchange conducting a scam project, it will jeopardize their integrity, and these exchanges do not want their integrity in question, so they only offer legit and promising projects IEO. New exchanges do not have the reputation to validate a project, they are just after the profit, SO they might promote a scam project either intentionally or unintentionally.
Maybe so! I remember some projects like CMA accusing IDAX of scam and then I remembered I have not really come accross a successful IEO from the exchange. While that may not be absolute, the purpose of IEOs was to eliminate scams from project developers during fund raising and I think that aim was achieved. So generally, IEOs went on fine