You are overthinking it, most people don't join the college to download illegal material using their neighbors' wifi. He just probably wants to connect with friends in the empty flat, or maybe just doesn't want to eat alone without entertainment. It sucks to be offline at home from 8 pm.
Stranger walks up to your house and asks to borrow your car. Forget that he could crash it, destroy it, use it in a crime, run people over with it, never bring it back. Naaaaah, He probably needs it because he's bored after 8pm and just needs entertainment. Sure buddy! Here's the keys.
Wow, talk about being naive.