Yes, your parents can call the cops if you leave at 17 in Missouri. This is because according to the state of Missouri's emancipation laws, minors under 18 are still legally considered minors and cannot make decisions for themselves without parental permission or consent. Additionally, since when you turn 17 you are still a minor in the eyes of the law, your parents could potentially file a missing persons report with local law enforcement if they believe that their child has left home without permission and may be in danger. While this might seem extreme to some people, it's important to remember that parents have an obligation to protect their children from harm and will do whatever they feel is necessary to ensure their safety. It's also worth noting that even though many states allow teens over 16 or 17 years old certain freedoms such as driving privileges or working part-time jobs, these rights do not supersede a parent’s responsibility for ensuring their child’s wellbeing and safety. Ultimately, leaving home at age 17 without parental permission is not advisable given the potential risks involved; however should you choose to take this route then it is important for you understand that your parents have options available which include involving law enforcement personnel if deemed necessary by them.