Why does Italo only require the name of the person making the booking
and not the other passengers traveling with them? Don't they need to know who
is on the train? Trenitalia wants names and birthdates. Just curious....
Neither Trenitalia nor Italo need to know the passengers' names. Conductors just want to see a valid PNR for that number of passengers, they couldn't care less if you are called X or Y. Trains are not planes, not yet, but Trenitalia would really like them to work the same way...
Deutsche Bahn does not need the other passenger names either. It is just a matter each rail operator's policy.
Unless, of course, you are traveling on a Bayern ticket which needs to have passengers' names written on the back. (Other lander tickets, too ?) Conductor loaned us a pen to fill it out.