The old bit of hockey wisdom is that referees often catch the retaliation, but not the infraction that inspired the revenge. It’s not always fair, but it does seem like a good thing to keep in mind.
In the case of a Game 3 exchange in the third period, officials actually caught both. Brad Marchand seemed to trip Chris Kunitz, prompting a slash from the Pittsburgh Penguins forward:
Both received a two-minute minor penalty for their actions, so most people were probably satisfied.