''On Apps like WhatsApp, Facebook, Snapchat, Instagram, Twitter, LinkedIn, Viber, when a user grants an app access to their camera and microphone, the app could do the following:

- Access both the front and the back camera.
- Record you at any time the app is in the foreground.
- Take pictures and videos without telling you.
- Upload the pictures and videos without telling you.
- Upload the pictures/videos it takes immediately.
- Run real-time face recognition to detect facial features or expressions.
- Livestream the camera on to the internet.
- Detect if the user is on their phone alone, or watching together with a second person.
- Upload random frames of the video stream to your web service and run a proper face recognition software which can find existing photos of you on the internet and create a 3D model based on your face.

READ MORE: http://www.newtribeng.com/sci-tech/are-your-phone-camera-and-microphone-spying-on-you/

True, but the developers are wise not to make it optional by using checkbox...else no one would click on it