There are several apps that allow you to input all your loyalty cards and just keep the numbers in the app. I have done this a little bit with splash ID but I hate handing over my phone with ALLLL my passwords unlocked and readable to a clerk at a store, I have only visited once. If Splash had a clerk mode then you could specify which fields were viable in clerk mode and the app would lock itself and need a password to see any other records. The fonts should be large so they are easily readable from a few feet away so i don't have to surrender my phone at all.