normally bounty hunters do not have so many coins to make significant dump on market. investorsare the pople who thingk that it will dump with the bounty token release and they can buy back later more tokens from the ETH or BTC if they sell before or during bounty token release.
This is especially true for all of those tokens that give huge bonuses to the people that invest very early, those people have no incentive to keep holding their coins because if they sell their coins at ico price then they will obtain 10% and in some cases up to 40% of profits just by selling their coins, in fact they can sell for a price lower than the ico price and still obtain profits, something that no one else can do.