Last weekend, Teresa and I were flown out to San Francisco by LeapFrog for an inside look at the operations of the company. (We'll have several articles to tell you more about what we learned and how it affects your family.) On the way home, though, I ran across something that you need to know about.

As we were in the San Francisco airport, waiting for our flight home, we decided to check for free Wi-Fi because, honestly, Wi-Fi ranks only slightly lower than oxygen as an important ingredient in my immediate atmosphere.

We found two wireless networks available there. The first was a T-Mobile network that required payment, and while I'm techie, I'm also cheap, so that was out. The other read "Airport Free WiFi." Well, that would be great, except for one problem: even though it's part of the greater Silicon Valley, the San Francisco airport has no free Wi-Fi!  I realized this immediately when, in my iBook's AirPort menu, the "free" network was listed under "Computer-to-Computer Networks." Chalk one up for the Mac OS.

In case you're confused, what this means is that someone in the airport--and probably at the same gate--was using his or her laptop to create an "ad hoc" network. Unwitting tourists would see this and log onto the network, thus opening themselves up to that person to hack their computers. I pointed it out to Teresa and then started looking around to see who it might be. I didn't see anyone using a laptop, and when I checked again, that network was gone, so that person must've realized I was aware of the scheme and hid.

I'll also add that this can happen in any public place, including a hotel. When in your hotel room, double-check the paperwork in your room for the name of the network before you log onto the hotel's free network. And check to make sure your laptop is set to join "Preferred" or "Trusted" networks instead of just "Automatic."

So caveat blogger--that free Wi-Fi may have a high price.