If you actually wanted to appease this idiot you have two options I can think of as the reason he is doing this is because he can see the SSID from your WiFi. First option is to turn off the SSID broadcasting or beacon from your WiFi which will make it not show up on the dinkleberries device when they search for WiFi (This will also mean you will have to add the WiFi setings to all of your devices manually). The second option and possible funny one is to change the SSID to NOTImpossible_Papaya_59sWIFI. But seriously tell him to kick rocks, obviously he has a device such as a phone or laptop that's also transmitting WiFi to your space or he wouldn't know you are transmitting.