"Everyone who's on board is listed on the passenger roster," Leia said. "You can check it for yourself. A significant chunk of them aren't even from a version of Earth, let alone Paris. If there's anyone you're actually concerned about, you can observe them for while as a cat, but trust me when I say that if Papillion were aboard the train, we'd know it by now. He's not especially subtle, and it with how little privacy there is on the train, I doubt any Miraculous related secret identities would last long, no matter how careful someone was."

"To make it initially? Yes; no one's perfect after all. To not correct it when they're informed of it, though? No. If someone is informed of a mistake and given viable options to correct it, but refuses to even take those options into serious consideration, then it becomes something they're intentionally doing. Whether it's out of fear, stubbornness, or plain old stupidity, it becomes their choice and their responsibility."

"And no, you can't look into the future. But you can get to know people. You can use your own judgment and experience to decide if they're worthy of your trust. You're very clever, as a human or a cat- despite all evidence to the contrary when it comes to your puns-; trust yourself and your own ability to assess someone's character. Could you make mistakes? Possibly. As I said, no one's perfect. But it's far preferable to the alternative."