I think I'm about to cancel mine. Rain in the forecast for Saturday and I'm not willing to gamble over $200 that it will be a clear night since the fireworks are "not guaranteed." If I do cancel it I will update my post when I see the refund hit my CC account.
ETA: According to my credit card statement, they refunded it the same day that I canceled it. I didn't see it update on recent transactions for a while so maybe they back-dated it when they credited the account, I'm not sure. It did end up pouring that night and I am very very happy I didn't pay $220 to sit out in the rain, even if the show wasn't canceled.