I am a Delta member with free bags also. Yes I have used the service a few times and they will not charge you once you let them know. The cruiselines will print out your tickets and such and they will know if you do get the free bags. So if anyone just tries to mark exempt and they aren't then they will know and charge you accordingly. It truly is a wonderful service out of Seattle. But you also has to have flights after noon time and anything before that will not work.