It is only right for those three exchanges' IEO, but might turn out to be wrong with IEOs from small, less well-known or unknown exchanges.
On a contrary, those exchange sites are reputable
As I raised my opinion above, it is only right for big exchanges.
Joining IEO remove's the risk of holding a bag of worthless tokens compare to traditional ICO.
With IEO all investors are secure that they can freely liquidate their bought coin after the IEO sale. While in traditional ICO it carries a heavy risk that the token/coin might not be listed on a exchange.
Investors will get nothing back if they invest into IEOs from small exchanges, that eventually make scam exits.