I agree that unplugging the iron after using it is "safer" than just "turning it off".
I had an iron that "turned itself off" - and I set it down on the floor to clear off the ironing board - not realizing that just moving it would turn it back on - I now have a melted spot on the carpet.
So - even with a self-shutting off iron - I also unplug it when it is not in use.