I want them to benefit from the offer, but have no knowledge of the booked trip. I've already secretly signed them up for the offer, but am unsure what options I have re: associating their FF number with the booking? i.e. If I link their number now, they'll be able to see the booking in their app and that ruins the surprise. If I don't link their FF number now, and do it later at a time when it's ok for them to know, will they still be able to benefit from the DSC promotion? If it matters, I'll be travelling on the same booking so it would already be linked to my FF number (for DSC).