Someone else's iPad keeps trying to Sync/Authenticate?

I'm using my college's Wi-Fi network and occasionally I will get the pop-up in the picture that I've attached.

I don't know who "Bentley" is and want to prevent this message from coming up again, and also prevent anybody from having access to my computer, or piggybacking off of my AirPort.

How do I do that?

Thanks,

Justin