Could happen. If it was a simple unintentended accident, it's regrettable the fan it happened to wasn't more gracious.
One of my 5 kids was prone to spilling his drinks and food during a stretch in his life because he just didn't pay good attention. Knowing that, there's no way in the world I would have given him food or a drink in a stadium sitting around other fans. It was for everyone's sake, including his, we'd have him eat where if something happened, it only effected him.