Even if you like making your MacBook Pro with retina display look awesome with vinyl or other kinds of stick-on designs, you may want to reconsider putting them on the machine. Apple is now telling their customers that it is a bad idea to use palm rest covers on retina display-equipped MacBook Pros.
According to a post today by Apple, using any kind of palm rest cover on the MacBook Pro with retina display can put the geometry of the display at an awkward angle when closing it. Due to the display being so thin and the device being precision-engineered to keep its slim form factor, this slight adjustment of the display’s clam shell geometry can cause the screen to suffer damage.
Originally Posted by Apple
With many palm rest covers being a mere sheet of paper thick, it would come off to most people as a negligible change in the way the machine closes. On the contrary, it comes off as a surprise to learn that the aftermarket product could actually harm the display instead of simply making the machine look cooler.
Apple does not make any references to the older MacBook Pro models and the issue only appears to be directed toward the 2012 MacBook Pro with retina display. That being said, if you have a palm rest cover for your non-retina display MacBook Pro, you should be fine installing it without any issues.
Sources: Apple via Macgasm