I doubt, however, that the average person would use the word "safe".
The word "safe" is usually used for environments where there could be some potential danger of physical harm. For example a steel factory, or a coal mine, or a construction site, could be seen as "unsafe" because of the physical hazards, which in the case of accidents could cause serious injury or even death, and talking about "safety" in these environments makes sense.
The word "safe", or "unsafe", wouldn't be the first word that comes to the mind of the average person when talking about, for example, tabletop games being played among friends at someone's home, for instance. It just doesn't make sense. It's not like there are serious physical hazards and a danger of serious injury at a tabletop game.
But these are exactly the words that social justice warriors use. For example, there's a recent blog post written by Phil Veccione, titled "Why Safety Tools Are Important To Me".
He is talking about tabletop games, like Dungeons&Dragons.
And no, the use of the word "safety" in the title is not just some kind of metaphor, or quip, or inside joke, or something like that. He is using it in complete seriousness. What does he mean by "safety"? Luckily in the post he gives us his definition:
"Safety – the feeling of being respected, having a voice at the table, not being bullied, being candid, and not having any emotions triggered."Nothing to do with physical danger. Everything to do with feelings and emotions. (On a side note, notice that last part: "not having any emotions triggered." Just ruminate about that for a second. He isn't even qualifying what kind of emotions. Any emotions. But I digress.)
I'm not going to go into detail of how hilarious and ridiculous the "safety tools" he suggests are (which are so ridiculous that even a kindergarten teacher would feel ashamed of suggesting them). Instead, I'd like to focus on that word, "safety".
Like with so many other words, social justice warriors just love to change the meaning of words and apply their own definitions to them. This is in no way concordant to what the average person thinks of when the word "safety" is used. Why do social justice warriors do this? Why do they take words and change their meaning to something so ridiculous?
I think that the idea behind it is to apply the word to a mundane situation, while retaining the negative connotation that the word originally had, thus justifying activism. Let me explain.
As mentioned, "safety" is generally understood to be related to physical well-being, in being safe from physical injury, trauma or death. Thus something being "unsafe" has a quite negative connotation that elicits respect and fear. Being in a warzone is unsafe, being at a construction site or steel factory without protection is unsafe, swimming somewhere where there are dangerous currents that could easily drown people is unsafe, handling power tools without proper experience and precautions is unsafe. All these things could easily result in physical harm or even death.
Moreover, being alone in the wrong part of town, known for its rampant criminal activity, at night may well be unsafe. People rightfully fear such things, and are careful about it.
Thus the words "safety" and "unsafe" carry heavy connotations to them. Which is precisely why social justice warriors have appropriated these words for their own purposes: They want to apply the words to their own preferred situations, while retaining those strong positive and negative connotations. Just by using these words puts emphasis and importance to what they are describing.
Likewise, if an environment or situation is unsafe, it usually demands action to make it safer. Which is precisely the other implication that they want to carry over with their appropriation. Calling something for example "upsetting" doesn't have a connotation that something must be done about it. Calling it "unsafe" does. Thus it justifies their activism. It even justifies their violence (after all, "dangerous" people, people who make the situation "unsafe", must be dealt with using violence if necessary.)
To social justice warriors feelings and emotions are "unsafe", and must be protected against. (Again, as that blog post just hilariously says, "any emotions".)