Well here’s a reason for shutting off electronics in flight, from Anna Leach:
>An iPhone caused a small emergency in an Australian airplane after it inexplicably started to glow red and emit “significant amounts of dense smoke” as the craft touched down in Sydney airport.
Check out the picture in [this pdf](http://www.regionalexpress.com.au/MediaRelease/Files/295_MR20111125%20-%20Mobile%20Phone%20Self%20Combustion.pdf).
[via James Wilson]