Same question I was about asking op, I have never heard anything as IEO bounties and I don't think we are going to here any even in the future, the work of this exchanges is not just to run IEO for companies and raise funds for them, but are in charge of marketing the IEO to make sure that the coin is being solved out in just few hours, so I don't see any need whatsoever to carry out any form of bounties since bounties where created for promotion.