She's book smart, not street smart.
Why y'all always assume that being a book smart means that you must not have awareness to the surroundings? She experienced negative behaviors from other people, she experienced hardships, and she of all people should be tempered to at least have vigilance toward others.
Take note of the fact the she already is living her second life and she actually has real life experiences. And that's plain ignorance if she thinks she can't be at least aware of what's happening around her.
Didn't say I disagree. It's just something the author has made obvious. Why worry about strangers when your own family is worse?
Should she not have opened the door? Yes.
The timing could have also been better such as the author having her read the message and hours later opening the door simply on reflex or from being groggy if it was the middle of the night. She hasn't been harmed by literal children other than her sister and, while stupid, everyone does stupid things. Ofc this is fiction and something's gotta give to drive the narrative. I wouldn't be shocked if the end of this chapter is a red herring anyway.
Why would they create a smart character with zero survival ability? She is supposed to be smart and vigilant knowing the hardships she endure. Fuck, stupid ass author with brainrotting plot. I'm gonna drop this shit coz I loathe this