Two fans in Dodger stadium caught back to back fouls during a Mets game (and, almost as importantly, the Dodgers lost, woohoo!)

From the article:

But USC mathematics professor Kenneth Alexander used Wednesday’s Dodger Stadium crowd size and game statistics — 40,696 in attendance and a foul ball count of 48 — to postulate the odds against Walker and Castro catching back-to-back fouls.

Calculating that only one of 18 pitches were fouled into the stands (other fouls stayed on the playing field) and factoring in the six fans sitting close by the pair, Alexander fielded the problem.

“One in 10,000 is the probability” that the pair would catch two fouls in a row, he concluded. He cautioned, however, that his specialty is probability theory in mathematical physics.

I assume that this is the odds per game? If so this should happen about once every four years? Anyone think this is number is in the right ballpark?