Before you join any bounty the first thing is to make research and read the rules if you join ignoring a rules you may end up with nothing that means you have waited your time doing nothing, why you have to do research is not to end up prompting scam ICO. Don't always forget to check the spreadsheet weekly it will help you know if you are given stakes or not.
Yah, you should be watchful to every bounties you want to join. Their whitepapers , ANN thread and telegram channels so that you would know the updates.