My daughter did this last January, she was 5. We were actually on our way to see Woody and she saw the crowd and wanted to see what it was. It was only about 3 minutes until show time. I told her about it and told her she probably wouldn't get picked because they only pick a few kids but she wanted to try. There was space near the front behind 4 boys who were all in red and had their faces painted like Dart Maul. I figured there was absolutly no way she would be picked standing behind these boys. WRONG! She was one of the first kids picked. And I think only one of the Darth maul boys were. (How heart breaking for the other three?
) I large majority of the kids wanting to be picked had on Star Wars shirts, and a lot of the dad's as well. Most of them weren't the ones picked though, it was very random.
Anyway, she loved it!