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).