Yes i agree, there are lot of bounty participants who causes the value of the coin to dump because some are selling it below the ico price. But most projects only gives 2% budget for bounty, so i guess that will not really affect the token, in the beginning yes, but after that, the price would stabilize
The main purpose I think why bounty hunters dump their coin right away is because they joined the campaign to earn money out of it but not necessarily thinking about investing.
And i agree that there's really a small percentage that goes to bounties for an initial offering so even if all bounty hunters dump their tokens, i don't think it'll cause a serious decline. Investors are the ones who would have that effect on a project not bounty hunters.