I thought the headline meant the Governor canceled the tea party until I read the article. It was the “city” of Cape Coral that required the organizer to obtain a permit and insurance which she (the organizer) balked at. Anyway, it’s all in the article but the headline should be fixed because it could be (was for me) misleading.
So, what happens if thousands show up anyway and refuse to leave?
Governments have all the power which you choose to give them. She made the mistake of notifying the city that the rally was planned, and they took that as an opportunity to impose conditions.