I agree that it is important to be mindful when using knives around non-knife people. That is *not* the same as keeping your head down and tip-toeing on eggshells; it's simple common sense.
I remember once at a gun shop that carried knives, I was handling some knives (I happend to be looking for a small model). The young guy working behind the counter asked why I was looking at a smaller model. I told him because it would be more discreet around other people at work. He pulled out his large-sized flipper knife, flicked it open, dramatically maneuvered it around in his hand and said: "I don't give a F* what other people think. If people get scared of my knife, tough S*, that's their problem."
Well, no, it becomes everyone's problem, because guys like that make it hard for people like me who carry and use knives responsibly. Technically, his point may have been right, but it's those militant thought processes and actions that scare "sheeple" into believing that anyone carrying any sort of knife is a nutcase. Nowadays, the vast majority of people in the U.S. do not carry any sort of knife, even a tiny pen knife. "They" are the majority, and yes, they do vote. I've even met martial arts practitioners who go all wimpy if they see you opening a package with a Delica.
I usually carry some sort of larger folder; a Pacific Salt, Military, Sebenza, or other. But for use in a potentially sensitive environment, I also carry a small SAK, or a small locking folder on me. And in fact, for most of what I do in a typical day, a small blade will do fine. Why bring out my Military to trim a loose thread off my shirt or cut paper when a small SAK, Cricket or Ladybug will do it easier and more discreetly? I often use a serrated Tasmal Salt, itself potentially scary-looking, to cut plastic strapping, but do so quietly. The people at work have come to appreciate the fact that I have the knife and it saves not only me, but them a bit of hassle as well. I have the larger folder for heavier duties, but in my typical workday environ, I've never needed to pull it out yet.
Jim