I have read story of bitcoin signature scamming their participants too (project not paying their participants for promoting them). No type of campaign is safe from scam therefore you just have to be conscious when joining a campaign. Be very vigilant when joining a campaign, note that there isn't any guarantee to get paid so don't invest all your mind and body into a project.
Hence why it's frequently suggested to only join signature campaigns that already gained a reputation here on Bitcointalk. And yes, everyone should be skeptical when joining campaigns, but with bounty campaigns though? It's almost next to guaranteed for bounty campaigns to be either a huge waste of time due to the coins/tokens being worth next to nothing, or the campaign being a scam.
Back into those years where bounties are still profitable where its participants hitting up thousands of dollars value of tokens that they had obtain which is somewhat a thing
that cant really be removed on someone's mind or an impression that they are hoping for even up to these days bounties without even realizing that those good old days were
already gone.Outcomes on most projects now are totally trash together with your precious time,effort and resources.