The only thing that IEO guarantees (almost) is the listing (not necessarily on this exchange). And so, in fact, the exchange is not responsible for the future of the project. Of course, IEO is more reliable than just ICO, but right after the listing there is a possibility that the price will go down for various reasons. Now it is euphoria, but there have already been precedents (VEriblock on Bittrex, for example). That's life.