Incorrect_meme
Makarov decided to let some of his children to experience how it feels to go to a real life school, Knowing that it is obvious Natsu is one of them, He can't just send the boy without his smart and responsible girlfriend.
Who may I say Natsu only listens to.
What if their location was at the School where Lucy's Brother ,that she never knew she had, and her biological father owns?
What happens in their Life in Japan?