Is one purpose of school to teach students how to be reliable and responsible?

I am teaching intro biology to 90 students. All of the other teaching assistants have strict policies about being on time for class and never accepting assignments late for any reason.

I don’t really care if my students show up on time. If they miss something I say in the first five minutes of class, it’s a bummer for them, but I don’t see any point in telling them not to bother coming if they’re going to be late. This seems to run counter to the point of education.

Similarly, I have had a couple students forget to turn in assignments before leaving the classroom. I have no problem with them dropping them off the next day. I saw the students and know they were actually in class; they just didn’t physically hand me the paper. One of the other teaching assistants had this exact situation come up and is giving her student a zero. I don’t see any reason not to just take the assignment as soon as the student can get it to me.

Am I doing the students a disservice by being too soft on them? Should I be enforcing more rigorous standards? Am I supposed to be teaching them to be responsible and accountable? Can’t I just teach them biology?