Unfortunately, people do tend to judge by physical appearance including factors such as a sex, race, disability, other cultural factors, and clothing. So I'm generally mindful of what I wear outside my house rather than what knife I carry relative to how I am dressed. I'm also mindful of my composure in public as this is often a critical component in the interpretation of actions or events.
If I am wearing a nicer pair of slacks, one of my better suits, or a tux, I do tend to carry a knife that can go inside of a William Henry Clip Case or a Clip Case with a similar design. But the reason for that is the knife is much easier on the fabric, instead of how others perceive it. But I suppose you could say it makes the knife less visible and more PC as well.
As a general rule, I prefer to carry knives with cosmetic styling features whether it be inlays, carbon fiber, wood, micarta, anodizing, colors, gems, etc. because in addition to liking the looks myself, I think it modified the mindset of the people not super comfortable with knives, as it moves from that whole "knife=weapon!" mindset to a "knife=artwork" or an "oh that is really pretty...what is it?" and completely changes the tone. I also prefer uncoated blades because I think they hold up better, but I also think they are seen as less threatening in some cases and I strongly prefer knives that do not mimic the whole 'Dork Ops tactical ninja' thing.
No matter what knife one chooses to carry and regardless of how they are dressed, I would strongly urge anyone to consider their style of and the context of usage and how that affects the way others may interpret such actions differently. For example, how one actually opens a folding knife in public can (and will) affect how people react. More specifically, many mechanisms such as the Benchmade AXIS allows opening that is faster than an automatic. If the knife is flicked open hard & fast with that authoritative CLICK, it could be interpreted very differently than if one manually and slowly opens it with two hands like they would a Buck 110 or a slippy. Another example would be judging the local culture one is within: a larger knife may be more accepted at some work places than others.
