This question deals with whether hiding an SSID makes a given wifi network more or less secure (short answer: neither). On the other hand, I think that a client that saves a connection to a network with a hidden SSID is opening itself up to a future man-in-the-middle attack.
Here's my scenario:
Alice connects to a hidden wifi network named 'Bob.' She saves the connection and sets it to connect automatically in the future.
Alice goes to the airport, turns on her laptop, and it starts searching for a hidden wifi network named 'Bob.' Malfoy is running a device that is listening for suckers like Alice who are broadcasting in search of a hidden wifi network. Malfoy's device responds to Alice's laptop saying, "Yep. I'm 'Bob'. And that password you've provided me, that'll do just fine. Here's your internet connection."
At this point, all Alice knows is that she's connected to the internet. She proceeds to browse the internet, while Malfoy sits in the middle stealing her info.
Now, if Alice is savvy, she'll realize that the 'Bob' network shouldn't be available at this airport and something's wrong. But that's a fair amount of burden to place on a user, especially a non-technical one.
So, is the above scenario theoretically possible? Is it practical? If it's not possible, what prevents it from happening?