it depends on the person if he want to sell it all after he/she get the bounty reward but some bounty hunters wait's the coin if it's rising or not.
Some bounty hunters can't wait for the rise of that token so as long as its already on the exchange, they are dumping it fast.
Those bounty hunters that are waiting for that coin's rise then they have knowledge on where that coin is going. They do believe that coin is going to be valuable in the future so that's why they are holding it. Verdict depends on the holder, sell if you want to or hold if you have to.