This is something that everyone with Wi-fi should do if they haven't already. It is surprising how many haven't given changing from the defaults a thought.
It doesn't even have to be hackers that trip over this kind of stuff -- just someone with similar equipment to yours that thinks they're working on their router when they're actually connected to yours.
That's a service you can render to neighbors that haven't changed their routers default passwords or set security. Log in and change the password for them, LOL