I’m 36 years old and I have my Disney autograph book from kindergarten. 31 years ago. Autographs from costumed characters are not a new thing. I guess it depends on what you classify as new though. But yeah, consumed characters have been doing that least 31 years.
I have photos from this time of me standing with maybe 5-6 other kids all hugging at the same time with people crowding around. It wasn’t like each person had a turn. All my photos from the late 80s have tons of other random people in them.
There are more people in the parks now than back then. And much safer for the character performer to be in a more controlled line so they can’t be accused of anything inappropriate or knock someone over, etc. They are able to prepare for the interaction. Also deters the people who think it’s funny to sneak and try to pull Pluto’s tail, etc.
Disneyland has some more spontaneous character interactions, but they still end up being pretty organized.
I do love these new character interactions they have started doing! I don’t see this as an either or thing - I hope lines for M&G come back someday, and that they continue these fun random appearances.