The world’s most secretive technology company designs computers in such a way that their cameras cannot be covered with anything other than 0.1 mm thick stickers:
If you close your Mac notebook with a camera cover installed, you might damage your display because the clearance between the display and keyboard is designed to very tight tolerances.
Make sure the camera cover is not thicker than an average piece of printer paper (0.1mm).
I tried a few covers after switching to the 2018 MacBook Pro and couldn’t close the lid indeed (I’m glad I didn’t damage the display).
This is in contrast to Lenovo, who have built-in covers in some ThinkPad models.
Apple touts the green light indicator as the solution:
The FaceTime HD camera built into your Mac computer is designed with your privacy in mind and uses a camera indicator light that glows green when the camera is active. So you will always know when the camera is on.
Previous MacBooks had a software-controlled indicator that malware could turn off while secretly recording you. What’s great about new MacBooks is that Apple designed the camera in such a way that powering it will automatically power the indicator. If the camera is on, the light will be on as well and it cannot be disabled via software.
This is good, but presenting the indicator light as a privacy solution is missing the point of camera covers. This is like telling someone who likes to walk naked around their house to not close curtains if they are afraid of being seen by neighbors, and instead to rely on noticing if someone looks at them. Camera covers are like curtains — the user can be 100% sure that nobody sees them even if they accidentally enable camera during video chat. (Which is especially important given the state of video chat apps usability.)
It would be nice if Apple provided curtains (or the ability to install them) for our windows the next time they upgrade MacBooks. I don’t think it will ever happen, though. To be fair, webcam covers were always a hack.