The answer, of course, is easily.
We have a history of terrible shootings. From the 1941 massacre by Stanley Graham, to the 1990 Aramoana siege where gunman David Gray took 13 lives, to this week's double homicide, there are plenty of examples of people going berserk.
We have people around us who are desperate, angry, violent, evil, insane, or living on the knife-edge between these states of mind. And any one of these dangerous individuals can wreak havoc at any time - from threatening behaviour to serious violence.
Certain people are at higher risk of being a victim. People who dabble in the drug underworld, become tangled in violent relationships, work in high-risk jobs such as policing, or who wander the streets at night alone are just a few examples.
But Ashburton has pushed another type of person into the limelight - the social agency worker.
These people work for a government agency or similar organisation and deal with people who have major problems - financial, child custody disputes, homelessness, criminal, and health just to name a few.
It appears these workers are more vulnerable than I ever imagined.
The day after Ashburton, the Bay of Plenty Times published the story of how staff at Te Tuinga Whanau Support Services Trust in Greerton are often subject to abuse from people who have reached crisis point.
These workers help people on a range of social issues and do their best to help those who really need it. And what do they get for their efforts? Threats and abuse from certain clients.
One example they gave is when they had to barricade themselves into their offices because of a threatening man while waiting for police to arrive. It is not the first time they have faced a dangerous situation and sadly, they say, it won't be the last.
In the days since Ashburton, there have been reports of Work and Income staff being threatened, a window being smashed and sites being forced into lockdown. More than 100 extra security guards have been added to the agency's existing security arrangements. This means some centres now have up to three guards and in Canterbury police are based in or near offices.
Readers might remember a case in March this year in which a parking warden helped restrain a man during a frenzied attack at Tauranga's ACC offices.
It is unfortunate that people have to face huge difficulties in their lives. It must be terribly hard to cope with financial problems, custody battles, feeling they are being unfairly treated, or not having a permanent home.
But lashing out at the ordinary people who are trying to help and make an honest living is unacceptable.
The frontline people who work in the likes of Work and Income, and ACC, don't make the rules. They work within the guidelines set by the Government and senior officials.
All clients, no matter how upset, need to show common courtesy, decency and respect.
Of course, for some this will be too hard. It will simply not be in their nature or they will lack the willpower to control themselves. Some will be angry or violent. Some will be good people who are incredibly desperate and lose their cool.
Work and Income has done the right thing by tightening security this week. It is important all social agencies, government or otherwise, review their security and ensure their workers are safe.
If this means security guards, metal detectors, strict admission policies, security bars and windows, and banning problem people - then so be it.
The safety of workers outweighs the rights of troubled clients.
