Secrets are definitely in the air: secrets of all kinds. Do your due diligence and try to uncover the furtiveness before you commit to anything. If you've known this shady person for a long time and you tend to trust them, don't get carried away: especially if you don't have all the facts. If you're not quite sure about them, based on past history, you still shouldn't make rash judgments. Go with your gut; ask around if you still don't feel comfortable.