Almost all projects scammed!!
Just a matter of research and you will find legit bounty I still see 5-10 bounty campaigns running that 95% seems legit if you are worried about token with no value some bounty has been listed on exchanges try to search them.
Yep youre right ,searching before joining is a must,not just that you saw huge bounty reward you will join immediately. If the bounty has low allocation reward pool but its 100 legit paying , then go join on that bounty.