The last time I had a seat in the actual venue in a product reveal was during the Steve Jobs era, and applause was definitely not coached — Steve was simply a gifted presenter.

These days, getting an invitation to a product reveal is a rare treat for employees (because there aren't that many seats), so I'm pretty sure the enthusiasm is genuine. I generally watch these reveals in satellite offices (where there are no cameras or audience for whose benefit one would have to fake enthusiasm), and there is still applause.