ACT (Action Counters Terrorism) e-learning is a free short course for the general public on what to be aware of and how to look out for terrorist activity in public places. A recurring theme in it is to be polite, to challenge people who are looking lost or suspicious, to ask if such people need assistance and offer to help such as taking them where they need to go. Essentially saying excellent customer service has a side effect of countering criminality.
It is interesting that by being nice and polite to people it makes it hard for them to be violent and anti-social.
What impact would it have on those who want to harm our society if everyone they came across in our society was friendly, open, polite, helpful in a self-assured way? Perhaps if we had such a society, there would be fewer people who wanted to harm our society in the first place.