Angelina I think it would be hard to have access to the key all the time but would not be allowed. From this aspect I prefer the way it is done in our home.
My father has a set of keys with him and another set is stored in envelopes in our save. Only my father and my brother know the combination, so in case of real emergency my brother can open us but not without the knowledge of my father. In a "life or dye" emergency of course he would give the combination to my mother, too.