Looked to me like to girl also got sprayed as she was almost BEHIND the officer. Watching carefully, you can see the silly string coming in from the left side. In thid case, the officer DID over react. Lawsuit time.
Even if she was the one who sprayed him, that would only justify arrest.
Police brutality, plain and simple.
At the 2-second mark, you can see a man in shorts enter from the left while his arm comes forward underhanded as he tosses a handful of something into the crowd of officers. The woman was hit by this same volley. Not once did she ever raise a hand to spray anything.