If you need to know the names of the other people in a reservation, why not just ask the guest?
The default message that I send after confirming a 2-person booking asks the guest for their arrival time and the name of the other person in the party. It's to the guest's benefit that they provide this information, since on many occasions the guests are arriving separately. If the other guest's name is provided, that person is effectively authorized to check in on the other's behalf.
However, I only rent a room for up to 2 people. If I were hosting large groups or families, I don't think I would find the names of every individual - especially the children - to be useful information.
As a side note, @Rosemary12 , if a guest is so seriously injured that they can't simply tell you their name, you absolutely shouldn't attempt to transport them to the hospital. In this scenario, calling an ambulance would be the right thing to do.