I think there needs to be a company specializing in combating fraudsters.
There is one already and you have access to it, it's called common sense, just use it
IEO is a lifesaver for investors if not for this,
IEOs are just well-disquised scams, that's all.
So they pay a fee, you buy their tokens and....what guarantee do you have those tokens will be worth something? None!
But you fall for it because the useless token is already on an exchange and you feel like this gives them some kind of legitimacy. It doesn't.
Just because you know the team, you know where their office is, they are listed on an exchange, they are paying articles to promote themselves is not a guarantee it will not turn into a scam. Remember bitconnect?Centratech? How would have an IEO saved you from it?
I think your idea is right in some sense that they have hid themselves in exchanges so that investors would believe they are real but I think is still better than not being listed at all.
Now, with the coin in exchange, you can also sell if you are lucky before a shit project gets dumped finally.