gchat annoyance

If you happen to use gchat at all, then you should right now log in to gmail, click settings->chat->Only allow people that I've explicitly approved to chat with me and see when I'm online.

I found out about this problem the other day after I had been emailing someone about renting a room at my house. Suddenly the next day, they showed up in gchat on my buddy list. When I looked I found that I had a shit ton of people added who were offline (many emails weren't even gmail accounts) and this kinda spooked me out. Tell your friends to turn this shit off, I can't see how it could be a useful feature.