A non-member was recently arrested in our main office lobby for attempting to cash a stolen check from one of our credit union members. A thief had stolen the member's checks and was writing checks to people all over town. The thief was convincing people to cash the checks at their own institutions in exchange for being paid $30 or so for their "assistance".
Our member had already reported the checks stolen which is why we contacted the police when one of the stolen checks was presented at the teller window. Possession of a stolen negotiable item is a crime, which is why the non-member at the credit union was arrested.
Please know who you receive checks from. The holder of a check is responsible for that check if it is cashed or deposited. If that check turns out to be a stolen check, you could face criminal prosecution for the stolen item. If the check turns out to be an insufficient check, you would be losing your money. Neither scenario is an acceptable risk for negotiating the check of a stranger.