I haven't seen this before although I'm sure some of you have.

Locator 1 = Only my name. A Club Europe cash fare to Jersey
Locator 2 = Two friends on the same flight in Club Europe booked using my avios
Locator 3 = Two other friends on same flight in Club Europe booked with avios in one of their own accounts

Seats were booked together on all locators on the strength of my gold card so the 3 locators were TCP'd

Using Locator 1 for check-in expecting to see only my name, but instead found all 5 names in this locator and was able to check everyone in and download all boarding passes in one go.

It did save a lot of time not having to retrieve all 3 locators separately to check-in everybody, but I was amazed to see all these people appearing in my booking.