Have a secret code word.
You and your parents should pick a secret code word that is easy for you to remember. This way, if anyone tells you to come with them because your parents are hurt or in the hospital, you can ask them for the code word. If they really are a friend, they will know the code word that you and your parents chose. If they do not know the code word, you should run away from them as quickly as possible and alert an adult you trust.