Events like that are intended to "hook" you. They're "perfect" by design just for the specific audiences. Do you expect a demo to show off bad points?
I never claimed it couldn't be done, only that I've never seen where it was given as a feature. If you choose to believe a demo setup to show only the good points of any device represents a feature in all cases, you are free to do so.
It's bit like all those beautiful hamburgers you see advertised by fast food joints. Those tall, plump, dripping with goodness burgers always turn out to be less appealing and squashed down versions when your actually unwrap them. The internet is filled with examples of what's advertise vs. what's delivered. And they all are clown acts.
It's called Marketing ... makes no claims but imprints on your mind all the good stuff; what you see is very often not what you get.