I agree with Judy on the necklace.  It should be fine for an older child, but I would be wary of putting it on a small child who will be climbing on things, playing on playground equipment, etc.  My daughter has worn a bracelet for 12.5 yrs now and no one says anything to her about it.  I think when she was younger she may have been asked a few times, but she would just say that if she got hurt, it told people what they needed to do.  If kids get any kind of explanation, they generally go on to something else.