True! I've thought of that. How could they stop hundreds or thousands of people who went in, carrying water, at the same time? They couldn't even arrest more than a handful.
Have you ever seen the movie "Zulus"? The police if under seige would form a square, similar to the British soldiers in the movie, and would fire volley after volley into the crowd until people moved back, dispersed, or were all killed. There would be a mass of dead and wounded bodies at the foot of the police formation.