I got that same check from "Just For Me" a couple days ago. The second blog link you posted seems to indicate that the scamming company could just charge anyone's credit card without authorization (i.e. me signing the back of and depositing that check). Is that how you read it as well? I periodically check up on my credit card transactions, but is there a specific offending merchant I should be watching for here?
This is so shady. I can't imagine it can be 100% legal.