>> I unlock it to peek at messages in meetings under the table.

> If you can look at the screen from a reasonable angle then it can see you and unlock.

You don't need to be able to see the camera to respond to messages in the bottom half of the screen. And even so, larger iPhones already allow double tapping home to bring the top of the screen down for one-handed interaction, which means you can already do everything but camera stuff (right?) with the camera obscured.