Absolutely yes im afraid with this cases, thats why i only trust binance when participating in some IEO to secure my funds to guarantee my profits, now i earn x3 profit from one IEO.
so far you might choose the right project and exchange for your IEO investment. because besides binance I also don't trust other exchanges that have the IEO. there are BW, LATOKEN, and others. I think the trading community in their exchange is not feasible for the IEO. and if there is a project that is successful at such an exchange, I doubt. maybe just manipulation from the team and exchange only.