This is an issue that should be attended to . Bounty managers should always have it that they need to assist hunters to get what their reward is. Some developers have taken from hunters what their benefits are.
There are some points that should be tackled about this...
1. Ensure that rewards are distributed before they go into exchange. This is because when the coin goes into exchange and starts performing and increase, developers find it difficult to redeem the promise. Dego bounty is an example on that.
2. Always have a good bargain protection for hunters so that no matter what, the reward will go to the hunter after the bounty.
3. Suggest payment in valuable altccoins because protection of workers should be important to any company.
Since past i never complained although sometimes get same experience too. But i think bounty manager will do their best to do their job because it will affect on their reputation. About distribution, usually it is from developer's team and i believe bounty manager wouldn't only silent and keep to follow up the team about distribution. If me, as bounty hunters when see the project is not good like to hold the payment, just talk in forum. Then their investor will know what actually happen to the project and market will decide whether the project success or not because of it.