"Yes, we already bought tickets to Matilda, but thanks for the suggestion to try the lottery. I wanted at least one show locked in. I may try rush or TKTS for a second show, but we'll see. We're only there 4 days and a second show would have to be a night showing (since Sat matinee is Matilda). Really looking forward to it and my kids are excited too from the YouTube videos and cd. I think my 6 year old will be ok (i.e. not scared). She was fine in Wicked, where the monkey at the beginning and the wizard mask are scary. And I've told her that Matilda's parents aren't very nice, but she understands the difference between reality and shows."
I've never witnessed any kids actually appearing frightened or anything during Matilda. I think most of them find the Wormwoods hilarious (so do most of the adults). In fact, there's a little audience participation bit right before the end of intermission that involves Mr. Wormwood and his son, and kids seem to love that part of the show.