`pop()` is used here: https://github.com/stuartf/Hilary/blob/6092b3f40d0bd3a1bef6f4b35145ded82c7a32de/node_modules/oae-principals/lib/api.user.js#L244

We iterate from the last element of the array to the first element, therefore validating that the last user from the CSV is in the list does not validate that you made it past 25, validating the first user in the list should do that.