You are absolutely right all IEO's which are conducted on low rank or new exchanges become scam and investors don't take interest in these types of IEO's or very less investors buy these IEO tokens. So always try to invest in IEO which is scheduled to conduct on high rank exchange.
Correct, there are so many IEO's there that's still providing a scam website or simply exchange. Those exchanges are not legal I mean they are meant to be decentralized to scam people/investors. I have some tips to know if the IEO is legit or not. First it is legit if it's on the legitimate exchange like bittrex, poliniex like that major exchanges. Second is if the partner of that specific IEO token verified their partnership on it.