It is not as simple as you think. Demonstration or rally can be done by 1 person or 1 million people. You can predict 10 but it maybe end up with 50. No one can guaranty. It is not done on the internet but physically appear at the stated location. When so many people gather at a same place for a demonstration, emotion is easy to be stirred up (if you are not pissed off, no need to stand under the sun la) and it is very difficult to control. When the demonstrators flood the road and effect the traffic, if someone got heart attack or whatever in the middle of it, it is almost impossible to send him or her to the hospital in time, even emergency respond team also may not able to reach the patient in time after pass through thousands of people. Other than that, the abnormal traffic congestion will effect others non related person. Including those who wanna go shopping and need to pass through the road or an ambulance on its way to send someone to the hospital. At this point, I need to remind some people that, you have the freedom to do your rally but you cannot force others to accept it. People do have rights to object your action.
OK, for saving your time, I skid the rest and just say the last thing. You have done 1000 times demonstration and all success. But whom can guaranty the next time will be the same? If no preparation and somehow the demonstration/rally turned become a riot, I can answer you, yes, and perhaps it is way more destructive than a bomb. That's why the enforcers will have to make road block/close the road or make some plans for initial preventive action.
We have laws and we should respect it. The authorities don't approve then seek for another way (in this case, several stadiums had been offered). A demonstration can be peaceful but why not pick a strategic place that will bring minimum negative impact to the supporters and innocent public? If the organization ever make a emergency respond plant or organize groups to control the situation if things turned bad?
I don't agree with Bersih's way of demonstration But I respect the fact that saying 'people do have rights to do a demonstration'. Setting up road block or closing certain road or even deploy the water tank to standby are part of the ER plan from the authorities. They have to do it according to the standard protocol regardless whom or which party control the gov. Even if organizing a RIOT is legal, the police force still have the responsibility to protect those innocent people who is not involved, be it 1million or 1 person. So, regardless how, the police have to do something and every country do have their own protocol according to the own culture, political situation, economy scale, infrastructure, and etc.
cheers
