The best I understand it, this Ulysses kid's brain runs all these probabilities to determine likely future catastrophes, and then he warns people about them. It's like psychohistory, but it actually can predict the actions of individuals, which is sort of crucial in a fictional setting where individuals can potentially destroy entire worlds. This has lead to much punching (or maybe it's still just arguing) about whether people should be getting prosecuted over things they are likely to do, but haven't necessarily done yet. The answer would seem to be obviously, "NO," but apparently not.
Beyond moral questions, I have to wonder how accurate this could really be.The Marvel Universe has multiple characters who have powers that alter probabilities such that things which would otherwise be exceedingly unlikely to happen, happen. Can Ulysses' power somehow account for the actions of people who, by the nature of their powers, should confound his?
Ulysses predicts the, I dunno, Rhino, will steal a gizmo that will cause the Atlantic Rift to open wide, dumping the entire Atlantic Ocean into the mantle, causing some sort of huge problem. This is a bad thing that heroes would reasonably want to prevent, but can Ulysses predict that Longshot's going to come plummeting out of the sky with a jetpack in front of the Rhino before he gets to the device, and he just so happens to have Rhino's dear, sweet mama, who Longshot rescued from an apartment fire without knowing who she was? And that this causes the Rhino to abandon his plan and take care of her, and the whole mess is averted? Even if there is a very small chance of that series of events taking place, Longshot's power set (or Domino's, or the Scarlet Witch's) means it's more likely than you'd expect, but I'm not sure if it would be in a way anyone could account for.
But even past people with powers that specifically mess with probabilities, the Marvel Universe is already a place where probabilities are out of whack. The things people survive that they shouldn't. The times some nutball cooks up a device that could actually, somehow, destroy the planet. The people who get exposed to radiation or dangerous chemicals and get powers instead of horrible diseases. The SIlver Surfer meeting Alicia Masters, and only then deciding to defy Galactus, and in the process, save the Earth.
Stuff that is exceedingly unlikely to happen, happens all the time. Ulysses being 99.9% sure "X" is going to happen doesn't mean a damn thing, because especially on Marvel Earth, that 0.1% possibility of something else happening in our world, is probably more like, what, a 25-40% there, simply because that's how crap works on that planet (and to a lesser extent, that universe as a whole). It's not necessarily to the point where what we'd consider improbable is the most likely outcome in the Marvel U., but it's certainly more likely than it would be here, simply because a lot of things happen there which can't happen here.
Maybe Ulysses' power adjusts for this somehow, though I'm not sure how that would work. "This thing that by all right should almost certainly not happen, actually has about a 1-in-3 chance of happening!" That just seems like it would break his brain. It doesn't invalidate the potential usefulness of his power entirely, but it certainly seems as though Carol Danvers and the rest ought to be taking it with a considerably larger grain of salt than they are.