Welcome to the world of Jeremiah the capital "P" Prophet. He was shown everything that was coming, and it all happened just like he saw it. He felt helpless. He wrote "Lamentations" out of his pain.
If I knew something dire would happen to you, would you want me to tell you? Knowing it was inevitable?
The record shows that even when people are told in advance, most of the time it makes no difference. The people of Nineveh are an outstanding anomaly; they actually responded wholesale to what they were told, but that's not how it usually goes. Back to Jeremiah, again. He had the whole timeline just dropped right into his lap; saw it ALL coming, and nobody would listen to him.
Still, he had to speak. The paradigm was given to Ezekiel, and it was this: if you don't speak, and they die, their blood is on your head; if you do speak, and they die, their blood is on their own heads.
The deciding factor there is accuracy; out of all the things you see, how often are you dead-on accurate? I don't know about anybody else, but if you're accurate, and you see something about me, I wanna know. Heck, even if you're only 50/50 I wanna know, but you should also say, "I'm only right about half the time."
Leave it to the other person to decide how to handle it. You tell enough people enough stuff, and they see enough of it come true, they'll start taking you seriously when you speak.
True story: The day I wrecked my truck I was TOLD, "You're gonna be in a wreck but you'll be completely fine."
I could have gone straight home; I wasn't that far away, but I figured that, since I was going to be totally OK, it couldn't possibly be that bad. Well, it WAS that bad; my truck was totaled; rolled up onto the passenger side and totally demo'd out. I climbed out through the driver's side window without a single scratch or bruise.
I'd sure like to have that one back; I'd have gone home.
I'm happy to have escaped unscathed but DANG I still miss that truck!
Sadly, the accuracies of time and place are seldom carved in stone. The people, however, are in my head for at least six months. This includes me. I nearly lost my life in January of ‘69, but I had no less than four months “lead time.”
I keep hoping if I talk about it, some of the “mojo” will be diminished. Not.
My accuracy rate is about 75%, sad to say.