Well I don't think that you wanted to promote a ICO isn't it. But if you are not careful in joining bounties there are chance that you might unintentionally though.
That's the risk of joining bounties because its like gambling, you don't know if the project that you are promoting will turn out to be a scam and of course you wouldn't received the tokens or rewards that you have work hard for.
Sometimes those scammy ICO are hard to detect that's why you need to be very mindful of projects you are willing to work for. Fortunately though, you can visit this https://bitcointalk.org/index.php?board=83.0 to see if the project you wanted to promote is a scam or not.