The WiFi Pineapple makes man-in-the-middle attacks incredibly easy, but users better know what they're doing before trying out the Pineapple at the biggest hacker hangout in the U.S. A classic example of that wisdom can be seen via a screenshot tweeted by @JoFo after an intern deployed a Pineapple at Def Con 22.
Feel free to see it yourself in the original form, but the general gist is below...with creative asterisk spellings for words I can't publish here. Hopefully you will be as amused by the message as I was.