[cloudmountain]

Being armed REDUCES the chances of shooting as the real cowards dare not approach whom they consider an "easy" target.
Gramps MIGHT be packing...and the old guy won't hesitate a second to protect himself and his family. BLAM!!!

[az_gila]

Sydney may have other imported hazards -

http://www.bbc.com/news/world-australia-34431926

http://www.smh.com.au/nsw/taxi-driver-mark-farhad-granted-bail-after-crows-nest-hit-and-run-20150819-gj2u9z.html

Could get worse than armed students.