But, to provide better security you should use WPA or WPA-2 encryption. With most home and SOHO (small office / home office) wireless routers, it is as simple as logging in to the Admin console, enabling the encryption, and setting a password. However, as this recent incident demonstrates, "simple" is relative, and enabling wireless encryption is easier said than done for many users.
The real answer, though, lies with the wireless router vendors. Unfortunately, convenience and simplicity trump security. Wi-Fi routers are designed to just work right out of the box. They live up to the claims in most cases--as long as your only concern is being able to connect to the wireless network and start surfing the Internet. But, if you also want your wireless network to be secure, they don't work so well out of the box after all.
Users who are not tech savvy, and want the convenience of a wireless router that "just works" are not likely to invest the time and effort to learn about the inner-workings of the router, or to understand and enable the security features. Wireless routers should be designed with encryption enabled by default, and part of the initial configuration should involve stepping the user through the process of establishing a unique SSID, and setting a secure password.
For now, though, that ball is in your court. Do yourself a favor and take the 15 minutes to figure out how to log into the admin console for your Wi-Fi router and turn on encryption to prevent unauthorized piggy-backing. If you don't, the next knock on your door might be the FBI--and they might not be there for pleasant chit-chat.