How do QF know you are/aren't travelling on a codeshare for lounge entry

[qf17]

How does QF lounge staff know that you are/aren't booked on a QF codeshare re granting lounge entry? Is there something on boarding passes that say it? Or have people had to show a copy of your eticket on QF stock? Off top of my head thinking of WP flying JQ intl booked on QF codeshare; WP flying LA booked on QF codeshare and so forth.

 

[Warragul]

Usually on the boarding pass. Something along the lines of "sold as QFxx_X".

Ultimately than can look at your booking in the reservation/ departure control system.