If somebody is a person who demands to get something for nothing from complete strangers and then get mad when they don't - well that person has very low value as a human until they can find enlightenment. These guys are definitely not in the majority of people.

There are reasonable reactions in this situation: Either be grateful that you got something for free, or accept that you were misinformed and pay what is asked, alternatively leave.

But let's be honest about this particular situation: The visitor had checked the event online, maybe first with ChatGPT and then on the official website. They noticed that the AI had made a mistake and thought they could abuse that to try to get in for free.

Everybody who works with the general public for restaurants, hospitality, events or retail recognize this kind of "customer", who are a small minority which you have to deal with sometimes. There are some base people who live their lives trying to find loop holes and ways to take advantage of others, while at the same time constantly being on the verge of a massive outrage over how unfairly they are being treated.