Put encryption on your network with a secure password. And remove the advertising of your wi-fi name. If people want on, they would need the name as well as the password. If your wi-fi name doesn't show then people won't try to get in.
Hiding the SSID (the network name) is not a valid security measure any more. These days, the programs “hackers” use to search wireless will detect the SSID from any network activity, since it is broadcast in the clear anytime a device communicates across the network. Actually, those programs have been capable of detecting a non-broadcast SSID for at least 5 years now.
While I don't disagree with the sense of your comment, let me add this: If you're using WPA2 encryption, and have a strong passphrase on it, you aren't really risking anything by broadcasting your WiFi SSID (name). And your legit guests with notebooks will appreciate being able to find it easily.
Sorta like, your house has a street number on it. Is that a risk? The lock on the door is what keeps the bad guys out -- covering up the street number only makes it harder for your legit guests to find your house.
That said, if you don't have guests who need WiFi, hiding the SSID certainly doesn't do any harm.
I wish there was a way to filter out offensive SSID names, they are all over the place.