If you are referring to the services being a scam then, try to find a bounty running by TokenMarket, BountyPortal or reputable bounty managers on the forums but If you're speaking about the members impersonating other members then there isn't much that can be done here. If the manager is vigilant, that shouldn't affect the original participant in anyway.
You can always tell the bounty manager is someone is impersonating you. There are a lot of scammers out there but if they don't succeed i think they will flourished if we will be vigilant.