We’ll never send any requests to your friends that you didn't actively send from the game yourself.
When you play connected to Facebook, certain events (passing a friend on a certain level, achieving a high score etc) can be displayed on your timeline/activity log, however, these are easily deactivated if you'd prefer them not to appear.
Simply follow these steps:
- Open Facebook and go to 'Settings'
- Choose 'Apps' from the menu on the left hand side
- Now find the game and click on 'Edit Settings'
- From the drop down list in 'App Visibility,' choose 'Only me' to prevent anyone else seeing these events on your timeline.