If we were to stumble into a Class 4 Outbreak, zombies everywhere/ world in chaos, or even in an early stage 3, I think everyone overlooks another big threat.
Survival.
Granted, a person can be calmed down. A person can be reasoned with, persuaded and even pacifed into commen sense.
However, in the middle of a zombie ridden world, mass hysteria is bond to happen and at some point we're going to find ourselves with resources dwindeling. Walmart food does have a shelf life, believe it or not, and people can get pretty nasty when they are starving, dying of thrist, in need of medical supplies or transportation.
And given the circumstances, they could very well be armed.
So, I'm sure everyone here is sound on where their moral stance is on killing zombies.
When in an outbreak you have to resort to Darwinism; survival of the fittest, if it benifits YOU to save someone you do it if they cannot help or be a benifit you let them go, you have to remember numbers can help and hurt if the group is too big supplies last shorter and mistrust spreads since human nature is that of mistrust so one problem will effectivly be everyones death, by human or un-dead hands, the only way to survive is to become in-human and logical and to appoint leaders, keep the group small and tight knit and you can prevent unnessisary loss of life.