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.
“IDGAF Special”

“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.
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