Not entirely true and not entirely false.  As bounty hunter, you have to choose which project will give you the most benefit, in terms of coins and exposure.  Many bounty hunters do not check whether the projects they pushed are scam or not, they are just after self-benefit.  On the other hand, some bounty hunters do check the projects if they are potential scam or not.  If they sense the project is a scam, they will exit quickly and look for other projects to support.