I could not at first understand why so many people were objecting to crib cards, but now see that often they are a mini-cardex, listing type of feeding, type of delivery, etc.

Our crib cards tell mom's name, baby's name and medical record number, and ID tag number, and time and date of birth.  And the color of the card lets you know its sex (sometimes the name alone doesn't tell you that).  Sometimes it tells which docs and nurses were involved in the delivery. Most of this information is for the family album, and not necessary for the hospital.  When mom goes home, she takes the card with her, as a souvenir.  

Of course, once you have total rooming in, the need for crib cards almost 
disappears. Our cards are used to identify which cot to put which baby into,
 not to identify the baby.  As our rooms are now almost all private rooms, 
this is even less necessary than it was when they were double rooms -- 
BUT babies still sometimes do leave their rooms, and if more than one 
baby is going to the same place at the same time, as for circs, it is nice to 
insure it goes back to its own crib when the procedure is finished.

Chanita, San Francisco