You can expect your ISP will hold you responsible. If I install an insecure wi-fi system in my home, and some spammer uses it to send a shitload of spam, I really doubt my DSL sysadmins would buy the excuse someone hacked my system. I might get lucky and just get LARTed; however I could very well just get my account toasted.
The easiest way is require password authentication. No password, no access. Note that stealing a car is pretty damn easy for an experienced and knowledgeable thief.
Is that on top of WEP and mac address?
Password would take care of guests at meetings rather well, establish a pw and delete it after the meeting.
The best security available on consumer-grade access points right now is Wi-Fi Protected Access (WPA). WEP is insecure and can be cracked in a couple of minutes. All other common methods such as passwords and MAC filtering are worthless, as any unencrypted information you transmit can be sniffed and then spoofed with commonly-available tools.
If possible use WPA with a nice long key. All your information will be encrypted and no neighbors or wardrivers will be able to use your bandwidth.
rfgdxm hit the nail on the head. I just use the basic WPA with pre-shared key. Filtering by MAC adds some more security. Also, you can’t approach my house within wifi range without setting off other security measures but obviously YMMV. As rfgdxm says, my point was more that stealing cars is pretty simple.
Anyway, in making the comment I did, I apparently completely misinterpreted drgnrdr07’s point. I thought he was saying that the fact that something was harder to steal somehow made it more illegal to steal. In fact, he wasn’t saying that at all.