Kbase Article of the Week: Using a Camera cover, Palm Rest, or Keyboard Cover on a Mac notebook →

Apple Support:

If you use a camera cover, palm rest cover, or keyboard cover with your Mac notebook, remove the cover before closing your display to prevent damage to your display.

To enable the thin design of Mac notebook computers, the clearance between the display (screen) and the top case is engineered to tight tolerances. If you use a camera cover, palm rest cover, or keyboard cover with your Mac notebook, remove the cover before closing your display. Leaving any material on your display, keyboard, or palm rest might interfere with the display when it’s closed and cause damage to your display.