Customs agents have the authority to conduct patrols at ports of entry to stop dangerous or illegal objects from being brought to the country. However the MSC Poesia was leaving the nation, not arriving. The passengers'possession of drugs in the U.S. was a crime, although not a crime customs agents are charged with preventing. Why were customs and border patrol agents active in the raid?
The answer might simply be that these were the people who brought the dogs. In United States v. Place and Illinois v. Caballes, the Supreme Court unearthed that the sniff of a police dog doesn't constitute a "search" because it doesn't reveal any information about which a person may have an acceptable expectation of privacy. If your dog alerts its trainers to the possible presence of drugs, the non-canine officers have probable cause to investigate further Veterans slam Trump for border 'stunt'.
Focus on the fact that a CBP spokeswoman didn't say just how many everyone was arrested, nor would she give their names. That information would let's follow up the real link between the raid. This seems like an exercise whose purpose was publicity, not law enforcement. As the searches might have been defensible under the Supreme Court's rulings, I imagine a good criminal lawyer would make quick work of a prosecutor's case for failing continually to prove who packed a bag, or whether the drugs might have been introduced at the dock or afterward by someone other compared to owner. But this may only happen if there were a really prosecution, which can be unlikely given the penny-ante results the raids produced.
Is this what we would like the Customs and Border Patrol to be doing these days?
We have already seen border agents run roughshod over civil rights - namely the best to travel within U.S. borders in peace - along the Canadian border. Employing their authorization to interrogate anyone inside a "reasonable distance" of a border regarding immigration status, CBP agents regularly question individuals on buses and trains between U.S. cities.(2) The Lake Shore Limited Amtrak train, which runs between Chicago and New York without ever passing through Canada, is just a particular favorite haunt for roving border patrols.
I'm inclined to believe that Americans smoking pot in America doesn't pose much of a risk to the nation, but it's even more obvious that Americans smoking pot in Honduras or Mexico, the MSC Poesia's two destinations, poses no threat at all. The Hondurans or the Mexicans may want to stop those drugs from entering their countries. In that case, they can conduct their very own searches when passengers disembark.
The potential harm due to the pre-departure search, on another hand, is actually evident. The cruise ship industry is an essential part of the Florida economy. Every Saturday and Sunday morning, from fall through spring, at least half a dozen gigantic cruise liners pull into Port Everglades before sunrise and disgorge their passengers, while others arrive in Miami, West Palm Beach and elsewhere round the state. They usually reload and depart on the next cruise prior to sunset. Fewer ships call at the port on weekdays and in the summer, but there's still a significant amount of activity.
This keeps a lot of people employed. There are individuals who focus on the ships themselves, those who drive passengers to and from the docks, people who sell food and other goods to passengers throughout their stopovers, and many others who directly or indirectly depend on the cruise industry due to their livelihoods.
While I don't have any great want to set about a cruise myself, I understand I'd be even less likely to wish to hop on board if doing this meant having my possessions scrutinized by federal agents that are on fishing expeditions. I suppose others who are more interested in cruises are probably equally uninterested in having their bags examined.
The cruise industry is focused on fostering an environment of hospitality and relaxation. Drug-sniffing dogs don't create quite exactly the same ambiance as, say, complimentary piña coladas might.
CBP agents have a vital and occasionally dangerous job protecting our borders, yet somehow this is simply not enough to help keep the agency from searching for other things to do. These extracurricular adventures have unpleasant police-state overtones. Someone needs to create the border patrol, along using its dogs, to heel.