And as I have just explained in that other comment, they did not ask for a verification code when I bought the ticket. They also did not ask for one when I tested that I could pull up the ticket after I installed their app. They only did so shortly before the show.

Perhaps somewhere deep in the terms of service that approximately zero customers have ever read, it says "Use of this ticket is contingent upon having immediate access to the email address associated with your account." Regardless, it seems unreasonable for them to expect that every user will have connectivity. If that is a requirement, they should state it more clearly.