I receive few bounties tokens with which i'm very happy because i joined bounty with full verification. Many bounty participants joined bounties without clarifying that is it ok or not? And may be you are one of them. The best way to check bounty is not scam is that- check their website is professional? check their roadmap? check their whitepaper? check their telegram channel and ask some questions? also check their ICO rating in popular ICO websites.