That's not a likely scenario. They aren't trying to create a Camry that handles like a Porsche. They're trying to sell Camrys. The effects will be subtle and plausible. To the extent that it's discovered, there will be excuses. And even after it's discovered, it will continue, just like everyone today knows TV car ads aren't real, but they're still effective, because they tap into the right parts of our brains.