I know what you mean, just about everyone carried a knife of some kind..
Year, and in 15th century in a European medieval town you could pretty much expect any man not to go to the street without his sword, or dagger, or a heavy stick…. These were the times! So what the men came to – weaklings!
If seriously, there are so many people in this forum considering a knife primary a "self-defence" weapon, that I am actually gradually shifting my own personal attitude towards people showing their knives in public. Though I have not seen many, I must say. Sometimes I suspect I am the only one with a knife in a pocket. But if I ever see one up close to me or any of my family, particularly somewhere in enclosed space, in public transport or in a movie theatre – I will most likely watch him quite closely until he returns it back to the pocket or moves far enough… You just never now what is in his head – what if he just waits for a pretence to show his self-defence skills…
I do not trust even dogs I do not know. Why should I trust some strangers with knives? Give me one reason. But do not tell me about tools – probably 30 % of topics on this forum alone are about how good the particular knife is for stabbing and cutting people…