Even everything above is followed correctly, still there's no guarantee that project will be good. However, if someone does enough research it's possible to avoid scam project. I am really bored on bounty and given up participating too.
The most important thing is that we as bounty hunters are constantly trying to find legitimate projects, for me to avoid this kind of thing is to join several campaigns such as blogs or social media in several projects. When I used to have a lot of free time I often did that and there were definitely some projects that would pay.