Anyone with first hand knowledge seen the bracelets yet? We have a latex allergy in the family so wouldn't be able to use them if the are latex. The allergy is more common than you think, so I hope Disney has planned for this contingency.
I also don't think it said anywhere that the bracelets will be the only thing. It sounded more like they were highlighting those because they thought they would be different and appeal to people.
From my view it looks like faux leather possibly. Disney also has other options available like key chains, the card, etc. (More were mentioned but I don't remember them all.)
Good answers so far, thanks everyone. I saw the times article that mentioned rubber bracelets and got concerned. Obviously not a bullet proof source, but it had me concerned. Especially with the rumor that they may offer charms and such to accesorize with it.
If you do an Internet search for either "silicone RFID bracelet" or "silicone watch bracelet" you will see bracelets very similar to the ones in the Disney photos that have been shown.
I had a watch with a silicone band and housing. It was not flimsy at all and the only structure that was not made of silicone were the watch pieces that were metal and the buckle (which was plastic).
Most hospital ID bracelets are made a fairly thin layers of vinyl with a space between for a paper with the ID band. They use very flexible and have little structure. I believe the hospital bracelets that go along with the Wanderguard systems to keep confused patients from leaving the unit are silicone.
I was told that you could swim in them if you wish, so they will be sturdy enough for that. Based on the description I was given from someone that had seen one, they fit the description Sue provided.