The useful ones ask a question, keep the answer, and let you change your mind after the thing is printed. Here is what that looks like for each job.
By job
The jar leaves the shelf and goes quiet. A code on the lid is the only way it answers back.
A code that asks a question instead of opening a page, and keeps the answer.
Warranty cards get thrown away. A code on the box turns registration into fifteen seconds.
Badge scanners are rented per show and tied to the organiser. A code is yours and works anywhere.
Catch the complaint before it becomes a one-star review, and know which table it came from.
