Engineers should be honest that everything is a tradeoff. For the up-front convenience you get with phone tickets, you impose additional failure modes, dependency chains, and accessibility issues that simply weren't a problem with paper ticketing.
The "phone-ification" of everything will probably bite us in the behind in the future, just like the buildout of out car-centric environments does now.
Even as a person who does have a smartphone, I feel like phone tickets are anti-convenience because they rely on terrible apps like TicketMaster. It's only a positive trade-off for venues or whoever. If they texted or emailed me a QR code, that would be a positive tradeoff (and a texted QR code would probably work for this guy's flip phone too)
Case in point: I traveled from St. Louis to Houston for a concert a few years ago. Before I left home to catch my flight, I installed the Ticketmaster app on a phone and verified that I could bring up the tickets. When I tried it again in my hotel an hour before the conference, it no longer worked because the fraud detection in their app was apparently confused as to why I was now in Houston.
Fixing this took 45 minutes on hold to get a support agent and a frantic call to my wife so she could check the disused email address I used to sign up for Ticketmaster 20 years earlier and get the verification code they sent.
There are a lot of reasons to dislike digital tickets, but this is one of them. I used to go to dozens of concerts every year. Now it's such a hassle that I don't bother unless it's small venue that doesn't play these games.
We attended a once-in-a-lifetime show last fall (a performer who is aging and likely won't tour again) a two hour drive away. I wouldn't install the Ticketmaster app and played an old man "character" with the box office to get them to print my tickets and hold them at will call. I played the "we are driving in from out of town" card, etc, and they accommodated me.
I tried that with a closer venue a couple of months ago and got told, in no uncertain terms, "no app no admittance". I knuckled-under and loaded the app on my wife's iPhone (which she insists on keeping because Stockholm syndrome, I assume). I feel bad that I gave in (because it makes me part of the problem). I really wanted to see the show and I wasn't willing to forego it on principle. (Kinda embarrassing, actually.)
Not to justify it, but we've been fighting this kind of crap for a long time with credit cards and their bonehead "anti-fraud" checks. I'm often on the phone with my credit card issuers every time I travel somewhere because their moronic systems think "different country = fraud" and lock me out until I call them and perform their pointless rituals for them over the phone. Even if you tell them in advance that you're traveling (which I object to because my vacation plans are none of their business), they still often get it wrong and flag you.
Don't do that. Create a new account with the email address you have access to.
Apps require you to sign in again all the time, and send a verification code to your e-mail to do so. Changing locations is, yes, a reason to require sign in.
Sorry, but that one's on you.
Because in the context of signing in, its role is that of a user ID.
Ticketmaster spams that address constantly. It's a valid email address, to be sure, but they've trained me over the years never to look at it. They certainly didn't do any multi-factor authentication when I bought the tickets, only when I was preparing to use them (despite having accessed them on that very device two days earlier).
This is the bane of my existence. I manually copy/paste/delete a half-dozen codes from my email/SMS every single day.
If I was ruler, I'd mandate every one of these switch to TOTP 2FA and outright ban email verification other than for password resets.
What? TicketMaster is the only app I use that does this. Probably because it's too hard for end-users to get rid of it. If some Telegram or some food delivery app or something tried to periodically re-prompt me to log in because I went outside my house or whatever, it would get uninstalled and replaced with something that didn't.