You can't ask anybody to stop promoting the project, It doesn't work like that. I thought IEO is the best way to stop scammer for now because a lot of scam project usually they give you token but never release on any exchange. but there is a project that doesn't even give you any token, but you can't really do anything about that.
I think IEO is an even bigger scam that the exchanges themselves are involved in it. but I could be wrong too. only time will show us what was the best way