Did you know if you lost your iPhone (4s or newer), whoever finds it can ask Siri “Who does this phone belong to?” – from the lock screen? Go ahead, give it a try and see what happens…..
This feature can be great, but depending on how you have your contacts set up, it could be giving out more information than needed, all from the lock screen. If Siri is showing more than you want or what you are comfortable with, you could go to your contacts and delete the information you do not want showing. But if you do, it would prevent you from utilizing some of the best features of SIri, like asking for directions back home or to call your mom.
Instead of deleting information from your phone, you can disable access to Siri from the lock screen by going to Settings, then Touch ID & Pass Code. Scroll until you see Allow Access When Locked, and when you see Siri, touch the button next to it to disable.
Now Siri cannot be accessed when your phone is locked. But if you do this, you might want to look into the app Find My iPhone, just in case you do lose your phone.