I mean, the Doctor, when you go time traveling with him, maybe he just invites you for one time. As a reward, or something, for helping him save a hospital full of people. He doesn’t warn you that he seems to attract trouble, which by now he definitely knows. He doesn’t warn you that if you die before you’re born, you’re still dead. Nope.
Or he invites you to come along, spur of the moment, because he likes you, and of course he doesn’t tell you that the two of you are going to fall hopelessly in love or that because of him you’ll be torturously trapped in an alternate dimension without him for what the both of you presume is eternity, nor does he alert you to the fact that just about everywhere you go with him you’re probably going to be held hostage, and a vast percentage of that time will be by a Dalek. I mean, really, it’s a fairly frequent occurrence, so a little warning could be in order. But no.
But Rose! Rose, when you time travel with her, she’s going to tell you straight out, “Donna, you die. You will do this, and your life will end.” Because she doesn’t deal with half-truths or deceiving people into saving the world. No way. If you’re gonna die to save the world, she’s going to let you know ahead of time, your life is what it takes for the world to be safe.