I recently had an early 2011 MBP start dying (3 beeps, I guess that's memory or GPU), bought a new 2015 MBP (old stock?). I was picking up a coffee cup, and the stone coaster came with it, and landed on the grill above the left speaker. I guess it's like getting the first dent on a guitar or a car, now I don't need to worry about the next one? Still mad at myself. And switched to a cardboard coaster.