While I usually do not condone more unruly behavior as the response to unruly behavior, it would have been heartwarming for the rest of those attending the graduation to publicly shame those idjits. Do it to the point that their baby runs out, tears streaming down her face, convinced she can never appear in public again.
Since going that route would just delay the ceremony, perhaps the shaming could be saved for afterwards when they are caught up with in the parking lot.
stay safe.