There might be a number of reasons for that:
- some individual people and groups, known troublemakers, were warned off. They included Mutiny, a left-wing group that distributed a manual for APEC that detailed how cause trouble; Resistance, a group that acknowledged on its website that other groups feared it would cause violence; and AC/DC, an anarchist political group (not the band)
- Police have lessons have been learnt from the Cronulla and Macquarie Fields riots of 2005
- rain, or the threat of rain, kept some people away
- the public holiday in Sydney
- pre-warning by Police that they would tolerate no trouble at all, and had the numbers and equipment to show it
- Protester fears that the protest could be high-jacked by those individuals and groups seeking violence.
Well, no - it is not the media's job to put themselves into a position that interferes with Police officers' work. The photo could have taken from the 3-5 metres without interfering with Police.
Whether the Police operations, and the special APEC laws, were excessive ought to be discussed as part of a debriefing. If a disaster plan, including preventive measures, means a disaster (riot) didn't happen, that is one measure of its success.