I can say 100% that 60% of all bounty is a Scam. The reward for them is either given and the tokens will lie on your wallet forever or do not give at all. Then what's the point of doing this ?
You may be right on this but you cant just stop others from doing bounties because they have been earning from it. After all, it will depend on how persistent you are even though you are unsure to earn. Also with experience from past bounties, people are becoming wiser and never easily get scammed.