Airport was enabled; however, the network name box did not have an option to "Join Other Network". I was very surprised, because I had used Airport to remotely install the OS in the first place, and that box did have the "Join Other Network" option.
I understand that sniffing tools, used by any network-savvy person, can easily find hidden networks. As a matter of fact, most newer network selection software distributed with network card drivers are able to find and display hidden SSIDs. I just like to use the most security I possibly can, and that's one tool at my disposal. Along with WPA2 and a strong key, the hidden SSID keeps my network out of sight and mind of the casual hacker who just wants to see what's out there to pick and poke at. They're most likely to hack at the easily displayed stuff and, hopefully, ignore what they can't see. Again, just one more tool - not the best, but not totally useless, either.