It will work, I have flown to ANC both pre-merger and post and never had a problem either time. There is no real time verification, the agent will write your mileage plus number and name in some log book. The view of the airport and surrounding area are pretty cool and the local beer on tap is delicious. The only negative is its the ANC boardroom is a bit of a walk from the gates that UA uses but the upside is, the food court / hudson news are located along the way.