Iroh in the live action 'The Last Airbender' does not have dreadlocks!! What he does possibly have is Jata; mostly likely to tie into the fact that LiveAction!Zuko is so obviously South Asian.
I can't read any more threads at the racebending comm on livejournal because I'm twitching too much at everyone describing Iroh's hair as dreads.
I know Bob Marley and The Wailers made the hairstyle extremely well known, but other cultures do have their own versions of locked and matted hair. For Hindu Holy Men and Rastafaarians the hairstyle is sacred.
For many African Americans I see with what I called maintained locs; the hairstyle seems to be about acceptance of themselves, their bodies, and their blackness.
But the terms dreads and dreadlocks are specific in meaning and really it's kind of like hearing a priest's vestments described as cosplay every time someone uses the words out of context.