Security guru Bruce Schneier points out that we routinely rely on the kindness of strangers, and that’s not a bad thing:
When I was growing up, children were commonly taught: “don’t talk to strangers.” Strangers might be bad, we were told, so it’s prudent to steer clear of them.As it turns out, this is profoundly bad advice. Most people are honest, kind, and generous, especially when someone asks them for help. If a small child is in trouble, the smartest thing he can do is find a nice-looking stranger and talk to him.
The advice in each of these paragraphs may seem to contradict each other, but they don’t. The difference is that in the second instance, the child is choosing which stranger to talk to. Given that the overwhelming majority of people will help, the child is likely to get help if he chooses a random stranger. But if a stranger comes up to a child and talks to him or her, it’s not a random choice. It’s more likely, although still unlikely, that the stranger is up to no good.
Another example:
If you’re sitting in a café working on your laptop and need to get up for a minute, ask the person sitting next to you to watch your stuff. He’s very unlikely to steal anything. Or, if you’re nervous about that, ask the three people sitting around you. Those three people don’t know each other, and will not only watch your stuff, but they’ll also watch each other to make sure no one steals anything.Again, this works because you’re selecting the people. If three people walk up to you in the café and offer to watch your computer while you go to the bathroom, don’t take them up on that offer. Your odds of getting three honest people are much lower.
This concept also works in computer security.