They'll look for pendant or bracelet. If it's really obvious they might (and the police will, but that may take time) look for an ICE type app on a smartphone. The medicos might loom through your wallet once you've got as far as Hossy because of the risk of complaints of sticky fingers, but if you need to impart critical life saving information that might well be too late. An example is Warfarin users who tend to carry a card in their wallet, but by the time they've got into your wallet you may be sat on a cloud, wearing wings and playing a harp.