a neighbour near me used to never leave her house without taking her bus pass, other ID, and contact details for her sons.
she did this even if only going for a 15 min walk in the park across the road, even though she had her phone, and I was with her and I had my phone too.
at first I was puzzled why she needed a bus pass to walk in the park. she said it was in case we were both incapacitated.
anyway, people who are worried about such eventualities could just do old fashioned note or mini diary in wallet or handbag, with details, next of kin, GP, allergies, also in car.