Upvote:1
What would be my course of action?
There's a few options:
Upvote:4
In general you can't. The airlines are responsible to check that you have proper entry documentation for your destination and will often be heavily fined if they screw up. Hence they do keep records so they can show What they did in case a dispute arises. These records are associated with the ticket number and quite often with you as a person.
Whether they every look at these records, compare docs, or care at all, is a different question, but you can't be sure.
To really achieve your goal, you would have to buy one way tickets with different airlines and use these airlines consistently for each direction.