In reality of course, Coast Guard and NYPD were involved because of the brawl.
"The Coast Guard's involvement included a boat crew from USCG Station New York escorting the ship through the New York Harbor . . . after our Vessel Traffic Service received the report of the incident at approximately 4 a.m. Tuesday morning," a representative for the Coast Guard tells PEOPLE. "After that, a boarding team from USCG Sector New York assisted NYPD and CBP with crew processing."
https://people.com/travel/coast-guard-escorts-cruise-ship-back-to-port-following-large-dance-floor-brawl/
It has nothing to do with Carnival ending room service an hour early so I'm not going to keep discussing it here as it is off topic for this thread. Just a symptom of Carnival's new bottom of the barrel strategy.