Private sale token should be locked for sometime for better price stability and good volume as well especially for tokens that are only listed on a single exchange or two, its one of the reason i don't worry myself much about tokens earned from bounty
Most of the old project's strategy is like this, they tend to lock their token so bounty hunters and investors won't be able to dump their coin for a certain period of time. It is to avoid their coin to decrease its value. But most of the bounty hunters and this includes some of the investors also are always in a rush of selling their coin. And this is the main reason why every project is always ending up to failure.
in my opinion the bounty hunter sells it too hastily, not so influential, because the allocation for the bounty hunter is only about 2-7% of the supply of tokens and does not really affect the price in my opinion. I agree with your opinion, if investors / popes are too in a hurry to sell it, it can affect the price. in my opinion the most logical is in terms of the products offered and the road map of the project, so prices will remain stable.
