If you're a woman just sitting somewhere, if you get talked to by a stranger 98% of the time it's a nasty guy who wants something from you, no matter how nice he seems. Most homeless men go ignored, most people won't even look at them, so ALWAYS ask yourself whether the person talking to you genuinely cares about a homeless person, or "cares about" a vulnerable woman aka potential fuck/victim. It's almost always the latter. Out of the like 50 men who offered me to come to their house, I only ever went with two, and I only trusted them because I was the one to talk to them first, not the other way around. Men are vile and dangerous when it comes to homeless women and you can't trust any of them, ever. They think that talking to you makes you owe them sex or something. I've had men scream and throw glass bottles at me just because I refused to come with them after talking for a while, as if I owed them. I was lucky I was in public and there were people watching us.
Always be aware of your surroundings, and listen to your gut. If a situation feels unsafe, even if you don't know why, leave. Don't stick around to find out.
The public is your friend. I've been lured into a dark alley before, because I tried to buy weed, and the ONLY reason I got out unharmed was because I said someone was waiting for me and managed to manipulate the guy into thinking I actually liked him and would definitely call him back, and he was stupid enough to believe me. That was EXTREME luck though and won't work most of the time. Most guys don't stop that easily and once you're in that alley, they can AND WILL do whatever they want. Don't make that mistake. If you have a bad feeling, don't go anywhere that's even less public. Don't go anywhere they try to bring you. Don't give them any control or advantages. Don't be afraid to ask for help from strangers.
Don't rely on your own risk-assessment to predict what a man would do. The public is your friend, but it doesn't always save you. You would think that "we're in public, people are watching, so no way he would actually harm me". This is false. Studies have shown that most men in prison either 1) can't make proper risk-assessments, they don't see the risks or possible consequences, or 2) they see it, but they don't care. If you feel unsafe, no matter where you are, get away immediately. Just because you think he won't do anything, doesn't mean he actually won't. You're only safe when you're away from him.
Most of my dangerous or scary situations happened because I engaged with those men that tried to talk to me. They would talk to me, and I would openly talk back. This made them think I was vulnerable, easy to manipulate. In retrospect, I should've been short. I definitely shouldn't have engaged in long, personal conversations, and DEFINITELY shouldn't have accepted anything they offered me. Meaning alcohol. They would see I was drinking, offer me a beer, try to feed me drunk and try to get me to come home with them.
Biggest warning signs I look for:
-he talks to me first
-he seems drunk, high, mentally ill or otherwise off
-he seems like he has bad intent, thinking about something else, rushes you or is very intense
-he was just talking to other men, but came to me alone. bonus if they're still around, watching us
More subtle warning signs:
-I feel weird, scared, or unsafe, but don't know why
-he asks me lots of questions, but barely talks about himself
-he tries to find out if I'm alone, if I have a boyfriend, or if anyone is coming back soon
-he tries really hard to get me to like him or to make me feel safe
-he touches me in "friendly" ways, even though we just met, or he comes too close
-he stares intensively, won't look away
-sexual innuendos, inappropriate comments, no respect for other women