Under normal circumstances, yeah. But this is a presidential campaign and both sides are looking for anything they can hit the other side with. It's the kind of mistake that could have easily been avoided if someone had done their job correctly.
And don't overlook the fact that Melania Trump could have been a real asset to the campaign. First reviews of her speech were all positive, and then it blew up over the plagiarism claims. After what the media did to her over this then I doubt she'll make another appearance again, and I can't say I'd blame her. So that takes away something the Trump campaign could have used to their advantage. And that's probably the reason for the hoopla to begin with.
Can you imagine how she feels. She has kept in the background. Her first big entrance and it blows up in her face. So many were talking about how well Romney’s wife did and how important this speech was ,etc.
I feel badly for her.