If you think "company might have faked public demo in some important way" is a "conspiracy theory", your conspiracy theory sensor is badly miscalibrated and desperately needs a tune up. Your default presumption should be that a demo is faked to at least some extent because most of them are. If I don't hear an explicit declaration that this is real and live and working exactly the same on stage as it will be for the consumer I assume it isn't. And even some of those declarations have been shown to be false over the years, a particularly popular one being "this is real game footage on the real hardware" except it's actually a developer box with a lot more power than the console in question.