Yeah the teacher is busy, they don't have the time to verify what you submit.
I used to try to phrase all my answers on tests and homework as uniquely as possible, because i thought regurgitating exactly what the teacher had told me was lazy. Turns out they're not thinking over every answer we submit, oops.
Haha I did this for my English Lit coursework, but I stole some Naruto fanfiction and replaced the names. My teacher asked if it was actually my work, and after I said it was he was super proud, said that he always knew I was gifted when it came to creative writing, and gave me a 96%.
This was early internet days when Google was becoming a thing, and people were learning about this awesome browser called Internet Explorer. I'm almost positive I stole Naruto, which was a brand-new anime at the time.