That is until the battery runs out and/or the cell network gets overloaded or something like that (not necessarily related to the power outage, but could be, depending on the reason why the power might be out).
Yup - just as the telephone line might also be done in the case of a storm cause power outage....
Anyhow, not worth debating or anything. Just thought it was an odd comment. I get not everyone does - but I have an 8000 mAh battery pack I keep charged up. My iPhone could run for days without being plugged into the wall.