Originally Posted by
ISTFlyer
I personally would not worry about a situation that has no impact, especially as entering your UA FFP in advance does not provide any additional benefit ( even if you were flying Economy Class ); although it's your choice to decide on what airline you'll fly with in the future.
I am worried anymore and, as stated on my previous post, it's no longer about not being able to enter my UA MileagePlus # at the time of booking or when accessing the booking afterwards.
In addition, I probably had the worst checking experience (without exaggerating a bit) of my long flying and frequent life, at LAX with a poorly trained or selected THY staff member (or sub-contracted employee).