Is it ever okay to make a (legal/criminal) mistake on purpose to fool the reader? Not in my book. Exaggerate a bit for drama, sure, but deliberately building a story on a faulty premise breaks faith with the reader. As prosecutor turned novelist Marcia Clark said in a panel discussion on forensics in fiction, "The more we tell the truth, the more dramatic it is." We don't need to lie about the facts to tell a good story -- we need to find the story to tell. Writers who take time to check legal terms and principles will discover terrific opportunities to twist, deepen, complicate and simplify their stories. Getting the details right can make all the difference.