Just because a token is listed on an exchange doesn't necessarily mean that it is 100% legitimate
Definitely true. And if a project's coin starts its life off scamming bounty hunters, that's not a good predictor for its future success.
What can we do about this crap? Nothing except for bounty hunters to stop giving these scam projects free advertising up front and then hoping to get paid in the end. The only solution to this that I can think of is for the project to pay the bounty hunters with bitcoin and to put the funds in escrow when the bounty begins. That's usually how legitimate signature campaigns work, and there haven't been too many instances of campaign members getting scammed. At least not nearly as many as with bounties.
But I'm sure that's been suggested before, and it doesn't seem like bounty hunters speak up for themselves for whatever reason. Since that's the case, they deserve what they get in my opinion.