Informal polls at author panels?

This year we'll have one or two panels dealing with specific authors, and I think it'd be useful if we start each by asking for a show of hands as to how many audience members have heard or, seen film adaptations of, and/or read works by each of the authors we'll be discussing.

Of course, even if most people in the audience have read a specific author, we have to keep in mind that some may not have even heard of them, so starting with a really basic intro to the author would be important. But if a significant portion of the audience are pretty familiar with the author, then we can go onto deeper discussion.