It’s the inaugural Arcade Expo in Banning, California. Walter Day and Billy Mitchell were there along with a crowd of eager pinball players, some of which would set a record.
“Biggest Little Arcade”
It’s unclear whether Ars Technica was also there. They have a picture gallery of the event regardless.
Fun With Bonus is the home of the semi-coherent, misguided ramblings of professional and amateur pinball players.