Seems pretty weird to require IDs for a simple ticket to a show.
Anecdotal but having visited a few countries that have national IDs, they use them with just about anything worth having. Tickets, SIM cards, Service Agreements, you name it.
I live in Uruguay and you need to use your ID very often when doing commercial stuff.
We're talking about football games, not a show in this subthread.
They're all the same to me. Entertainment.
Not really, risk profile is totally different between football game and opera.
Tickets are transferable. Not-banned persons can give them to banned persons.