I personally don't like the necklaces, I think they are kind of gawdy looking. I'd have trouble wearing it all the time and was surprised last year when it was a "rule" to wear it at all times.
I'd be interested to know the shipwrecker's answer to nicOley's question. I also wonder what kind of restrictions were in place for what they were allowed to bring. Can they bring lighters? What if it was a sentimental lighter that my grandfather gave me on his death bed and means a lot to me and just HAPPENS to produce flames too?

How about a great big 10kg bucket of peanut butter? They don't seem to stringent with their own rules of 'back to basics' anyway. They seem to have matches now.