Originally Posted by
Adam1222
The ethics of this have been debated on other threads with different airlines. But the converse of your idea is that aerolineas is paying for lounge access, etc., and not getting anything in return. You are not building your loyalty to the airline, flying it, or accruing status to be used on future flights.
Nonsense. Nowhere is the rule that you seem to have invented spelt out. Some airlines have such a policy (TK, I believe, does) but most airlines do not. In fact, airline reservation systems typically have two different field: an FQTV field for miles accumulation and an FQTS field for FF status and there is no requirement that the two fields are filled identically. Now, having two different FF numbers in a reservation is unusual and many agents do not come across it very often and many might not even be aware that there are distinct FQTV and FQTS fields.
The fact that they exist, though, makes it clear that using one programme for miles accumulation and another for status is not the absolute no-no that you assume.
Most airlines will allow you to change your FFP number at the gate if you wish. If your argument was true, they would not let you do so, would they?