We can more trust in IEO because, it will be directly be listed in an exchange, in ICO, it took them months or year before it happens, some of them does not list their coins and run away with their money that has been raised. In IEO we may see the exchange that they will be listed right away.
If it is true that many people believe in IEO, it will be easier for them to sell the coins through their own platforms, right? and I think scammers would dare to do this because their coin are clearly registered and can be exchanged. Until they reach the target they will run away.