I use the Dice app a lot but for tickets for small club/pub venues where they have never asked for the barcode - person on the door usually has a printed list , a pen and ruler , asks your name and then smudges something on your hand.
I've been to gigs recently where the average age upstairs at the live band was probably 50-60 and downstairs in the bar the 20-30s were out for the pub quiz.
I use the Dice app a lot but for tickets for small club/pub venues where they have never asked for the barcode - person on the door usually has a printed list , a pen and ruler , asks your name and then smudges something on your hand.