Just as much as we have seen a lot of them succeeded, does not mean it is a totally scam free means of token sale or marketing. Why because, there are some newly lunched exchanges, that have not spent so much time in the crypto space, yet are aspiring and already making moves to conduct IEO.
well, one of the arrival of that successful a project at the time launched with the IEOs.
One reason of back IEOs is I think that to reduce the failure rate at the time of fundraising with one of the IEOs will be seen many among as investors, traders, small communities who want to contribute a lot of aspects will the success of the IEOs.
so, I guess there is no limit to the people participating indeed and it depends on each individual while they analyse a project