Interesting question.
I have no idea where I learned – it was way back in pre-internet days, I’m sure – the idea that one of the modern meanings of a handshake between men (never mind the ancient antecedents about determining whether the person being met had a weapon up his sleeve or not) was an internal assessment that each man might make about the other – based only upon the handshake itself, eye contact and posture – was, “Can I kill him if I need to?”
I used to enjoy shaking hands with that explicit thought in my mind, not in any kind of violent or malicious way, just “consciously” with that in mind.
These days I’ve learned alternative explicit things to keep in mind, thanks to some helpful Facebook pages (Active Self Protection and Conflict Manager, if anyone cares to look ‘em up, as well as the blogs that some writer friends of mine – former active military – post on the topic from time to time) which frequently contain curated security camera footage of “social contacts gone far wrong”, from muggings and robberies caught on camera, to street fights and outright murders caught on camera. (The ones containing heavy violence and murders are delivered with plenty of upfront warnings: these are not “shock” sites, but even horrible tragedies can contain lessons for those of us who care to learn them.)
So I’ve become “conscious” in ways that I never before felt a need to be, about who is around me, the interactions between others when there are multiple people around, what others are doing and where they seem to be going, rate of travel speed, the potential for ambush, lighting and shadows, etc. In other words, “general threat assessment”. I don’t feel “scared” as a rule, but I am respectful of risk. (I won’t say that “I never get the wind up”, but I’m not often surprised, anyway.)
As others have stated, my default position on people is to assume that they mean me no harm. “I’m Okay; You’re Okay.” After all, I travel in and visit generally “safe” places, and everyone I know is “safe”, to the extent that I can tell. But I don’t do that blindly or unconsciously any more. I look, and I do assess, and not just for myself. I also look around to assess potential threat to others, whether I know them or not. So when I make those routine assessments I have, in fact, made explicit decisions about the “others” that I see.
On the other hand, I don’t feel “hunted” in any way. I’m getting older, but I do not move feebly, or with my head down (or in the clouds), and I generally keep my phone in my pocket – and my hands out of my pockets – while I’m out and about. I don’t feel like a sheep, more like a sheepdog getting along in years. I’m not looking for a fight, but I can still bite.
As to your specific questions, since I live and travel in mixed-race areas, even though my workplace is “mostly white”, I’m not highly conscious of different ethnicities, and certainly not bothered by them. I’m more aware and alert to age and activity. I don’t mind young people, unless they’re strolling across a busy street, for example, in a way that is likely to block traffic – or get one of them hurt if the driver doesn’t see them in time – or parked across the street from my house for longer than is necessary (I live across from a T-intersection on a moderately busy road), or wandering with apparent aimlessness, for example, in a place where others are moving more purposefully – or not moving at all, when that seems inappropriate. I’m always “just looking”, anyway. If I consider any other explicit markers that I look out for, I’ll try to get back here.
Part of my “problem”, I guess, is that I spend so much time in “safe”, that I don’t really have a basis for comparison – other than the videos that I watch from time to time – to “spot the unsafe condition”. But I’m more aware of where those places might be now.