Over these few years, I've come to realize tat our local "anti-terror" officers and chums look for obvious signs. These signs are usually closely associated with the way we dress, hold our cameras and wat camers we use.
I've realized the most effective way is to dress and look like a tourist. The most successful outfit is a bright "holiday-look" short sleeved shirt, bright cargo bermudas and wear a big "outback" hat. As long as you look bright and cheerful, they don't seem to bother you. Even if they do, they smile and talk to you clearly and slowly... just in case you no understands the engrish...
Why this is so amazes me and saddens me as I feel that their focus is all wrong...
1. Locals are probably suspect.
2. Happy looking tourists are not suspect.
3. Brightly coloured and gawdy looking dressing cannot be suspect.
4. Dull coloured of reasonable dressing is suspect.
If I were a terrorist, it wouldn't take me long to realize this way of spoofing the guards.