I usually book my travel through a company travel agency, which adds my MP number into the reservation, and it automagically shows up in my app. Steps to work around this (thanks, mherdeg! added a couple points for detail):

1.- Create a New Traveler under your account. Just add name, birthday, and KTN (if she has PreCheck). DO NOT add the MP number. Email/address? Yours.
2.- Ticket the reservation. Don't call in to add the MP number.
3.- Show up to the airport. Once in the counter, she will be able to add her MP number and get all accruals/benefits.

Q: Will the traveler be able to use PreCheck?
A: If the traveler has a Known Traveler Number and you enter it, yes. MP numbers have nothing to do with PreCheck

Q: Will the traveler be able to get PQMs/PQSs/PQDs/RDMs/benefits for this trip under their MP tier?
A: Yes. Just show up to the counter and have them add the MP number to the ticket. Bear in mind, CPUs will not clear in advance as the system doesn't recognize the traveler as a Premier until they hit the airport. You will have to fight the battle.


Do you guys think it's worth to make a wiki out of this? I believe this question can pop up frequently and maybe others can benefit as well