I guess bounty hunters don't think it all through when it comes to choosing which bounty they're going to participate in. more bounty hunters are randomly signing up for the recently launched bounty campaign. they don't care about project research.
They have time to experience by themselves with bounties and later they will realize that most of bounties don't worth their time. They can receive tokens if project teams are good and distribute tokens as promised or they can not get anything if projrct teams go scam and refuse to distribute tokens at the end. Even if receiving tokens, value of tokens can be nearly nothing.
They can do research to avoid scam projects if they don't want to advertise for scammers but no perfect results from their researches. It is hard for newbies to know what are good what are scam projects.