As long as the IEO is conducted on a popular exchange then it could be safe for investors but recently I found some new exchanges offering the same service which is not recommended since they are not known in crypto space.
Just today it is a new trend and all exchanges are trying to repeat this success,because it attracts investors.
Perhaps when the IEO is held on a well-known major exchange - it is safe,but does not guarantee the success of the coin. Recently, the VBK coin demonstrated this on the Bittrex exchange.