Now the story has changed as it only serious projects that would want to go through IEO's, we no longer would hold only the project body responsible for any IEO scam but the exchange, so any exchange that values its reputation and users should do a proper scrutiny about any project before accepting their IEO sales. For instance if an exchange fails multiple times with their IEO, it will drive attention away from them, that is why Binance still draws a lot of attentions because it has recorded more successful and profitable IEO's.
Exchanges should be able to identify a fraud project before it get listed on their IEO.
Their reputation will be ruined if they failed to avoid scams and frauds, even traders will leave them.
good exchange like binance must be have a certain way to verify the legality of the project.
I am sure they will taking care to select the right project to be list on the IEO. They will make sure the member will not get scam by the projects, and I think the project needs to pay some amount if they want to be list on the exchange, so the team doesn't scam the members. I think that it is necessary to prevent scamming because that will be related to their reputation too.