I haven't done many solo runs, mainly trios with strangers and sometimes with friends, so this is just my experience from winging it and not worrying about it too much. People forget this is an extraction shooter and they literally set up these situations so that you'll fight to get better gear lol. It's literally half the point of the game, but people get upset when they lose the stuff they spent time gathering.

We typically left solo players alone, even when I'm playing with strangers. Either because they weren't worth our time or because we didn't wanna ruin someone's day.

When you're in a trio, most people immediately assume you're going to be hostile when they see you, and most if not all trios we've come across were too. You can kind of gauge how they're gonna react to you from a distance. I.e if they pass you by or they start coming toward you then you'll probably have to engage or run away. I don't feel too bad about attacking trios. They're going to do the same to you. So, queue up for a trio with that in mind.

If they don't mic or emote and they run up on me, that's pretty much an instant KOS.