Originally Posted by Silverado
Why is it a mistake? A phone that no one can open except service centers... where do you suggest they put it? Other phones put it under the battery, where every store/dealer can check it. Looks like a perfect solution to me. It seems that you're assuming it won't work. How do you know? It apparently worked in this case. Do you think Apple didn't test their water damage indicator and that it just doesn't work and they don't know it?
Well, it depends how sensitive it is. If its like most cell phone stickers, then putting it where it can easily be subjected to humidity is a really bad move.