no, i think IEO prefered to protect investor not bounty hunter, as i know my friend participated in bounty campaign and this campaign launch IEO and the exchanger make rules for not running bounty campaign for the project, that's why IEO not proteting the bounty hunter but Investor
it is only for some rules of exchange, not all exchanges provide the same rules. many projects also carried out the IEO and continued to run their bounty campaigns. but it does not guarantee that the bounty will be paid, because I think the IEO or ICO will still remain the same.