I also believe it is much worth to live with a strong faith in the good nature of people.
However I believe one should not indulge in it.
This faith is very precious and this is exactly why it is a sin to rely upon it in the wrong circumstances.
I live in Japan, that has a very low crime rate, but I found it very interesting when they told me "Don't leave anything valuable at the office. There is very little chance that something might happen, but can you imagine how you will feel and act towards your colleagues if something happens..."
What you value you must protect. Although it sounds controversial, this means that it is your obligation to protect your faith to the goodness of people from the ones that could destroy it.
However I believe one should not indulge in it.
This faith is very precious and this is exactly why it is a sin to rely upon it in the wrong circumstances. I live in Japan, that has a very low crime rate, but I found it very interesting when they told me "Don't leave anything valuable at the office. There is very little chance that something might happen, but can you imagine how you will feel and act towards your colleagues if something happens..." What you value you must protect. Although it sounds controversial, this means that it is your obligation to protect your faith to the goodness of people from the ones that could destroy it.