By "passenger services" I mean planes, cruise ships, trains, etc. – any company that transports paying passengers. I ask because a few years ago a friend of mine had a sister who became very ill on a cruise ship, and wanted to get in direct contact with her (she lost her phone) and narrowed down the few possible ships she would be on to get confirmation of her health status.
He intended on contacting the cruise line and cross-referencing his sister's name with the cruise ship identifier (which would designate the cruise ship itself). He never did this since she called, but it does bring up an important question: are passenger services obligated to provide the names of ALL passengers on board in certain circumstances, or is this information private and it can't be given?
Everyone who boards a plane, ship, etc. has their name known by the company.