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.
How do you even know that it is "100 legit paying"? The payment is dont after the bounty completes, the projects token gets listed and so on. It used to take like several months upto a year to get those things done and some hunters would end up forgetting how many bounties they had joined in the first place. 
Low allocation does not mean a thing. A failure to raise funds and/or bankruptcy can always occur and the investors will suffer for that, so will the bounty hunters.