Won't say it'll *never* happen, but I don't sleep at airports these days. I occasionally did it in my student backpacking years and never had any issues. Passport/wallet well-secured on my body; not much of value in my carry-on. The few times I did it were airside in major international hubs...usually there was a fair degree of 24x7 activity so personal safety was never a concern.

It would take a pretty massive snowstorm to force me to sleep in an airport now. Something big enough to prevent ground transportation from running. I see these videos of people sleeping at O'Hare and my first thought is: isn't the CTA operating? I get that the Hilton and nearby hotels are probably sold out, but I know the entire downtown Chicago area isn't sold out in January. If somebody tells me it's going to be 12 hours before my next flight, there's zero percent change I'm staying at the airport if I can avoid it.

(If somebody tells me that the train *doesn't* operate in the snow, then it'll make a bit more sense. But the short news stories never mention it one way or another.)