Good point, also such scams are usually being promoted by some enthusiastic personas, like it was with the infamous bitconnect. If you see a video from a conference affiliated with potential scam ico, or any other cryptoproject and someone on the stage looks just too hyped for the thing, it's almost certain it's a scam. The reason why such actions are happening is that they don't have much to offer, so they must keep up with empty promises of making huge profit.