Assuming that his node is misconfigured just because it spent a lot of data within 6 days is foolish at best.
Your node could easily send out terabytes of data in 1 month if you don't restrict it.
I added some color for you. Misconfiguring a node with some ridiculous maxconnections (running it wide-open) is possible
What are you talking about? Running a node with the default configuration will easily use this much bandwidth.