Understandable.
I don't know if you've ever seen it. But, I think back to a video the DIS crew did a while back. And Steve Porter was talking about Trattoria al Forno breakfast. And, the way that works, is there is a character breakfast price, and there is a non-character price.
But, he talked about how it was kind of uncomfortable, because all these little kids wanted to go up to the characters. And sometimes, the parents just let them and didn't try to control them. And sometimes the parents did intervene, but there were many crying and disappointed children.
I guess I am just imagining that on a much larger scale. And yes, obviously people would be like you and have that discussion with their kids/grandkids in order to prepare them. But, many won't. Many may not even be prepared for it. And, I love the US, but I have to imagine our folks won't be as polite as those in Hong Kong. So, I'm imagining people screaming at the servers/CMs about "I paid a lot of money..." And then I imagine character wranglers having to control a situation in which parents are not following the rules and they are being forced to intercept other people's kids.