This is the keyboard test, also used by our magazines. It s not possible if you re talking about bleeding edge technology, but otherwise folks should leave your sessions itching to get to a computer. Tell them where you screwed up. Attendees know the real experts try new things, make mistakes, figure out what they did wrong. Take attendees on the trip with you.
People expect to get what and who they paid for.
Even a great substitute is still a substitute. Imagine buying tickets to Les Miserables, and the curtain comes up on Cats. You d feel outraged even if you liked Cats. Fly in the day before, so a missed flight doesn t mean a missed talk. And stay a day after, so you can see what other sessions, speakers, and attendees are like.