Show me an example of other types of speaker grills on Apple products.
Where did I say they used this for speaker grills alone? It's irrelevant, because it's a common design element:
Mac Pro case
Mac mini case
Bottom of the iMac for speakers
and the Mac Book Pro, as you've pointed out.
And that's only current products. Any other work I can do for you?
It's not that Apple might or might not do it, but rather that it's obvious that "thing" in the picture isn't a real device. Look at the finishing touch on the hole and especially the dock port. That's not a real iPad.
That's fine; I'm not arguing that point either way. I was responding to someone who said 'Apple would never do something as bad as X' when Apple clearly does X all the time. Unless they mean something more specific, for which they are free to respond.