"Lower tourism activity will definitely have an impact on growth," said Marco Oviedo, head of Latin America economic research at Barclays. "External tourism is one of the most important sources of income in the current account."
Mexico gets about US$20 billion (NZ$29b) a year from tourism. With murders quadrupling in Los Cabos and doubling in Cancun this year, a chunk of that revenue may be at stake. Quintana Roo, the state where Cancun is located, is the destination of a third of all the nation's international tourists.
In Los Cabos, local and federal authorities are teaming up with hotels, time-share companies and the airport operator to step up the area's security.
The group is spending US$50 million to increase surveillance cameras to cover the 20-mile main stretch that includes hotels, restaurants and public beaches. A new military facility, paid for in part by the private sector, will be built near a highway to respond to any activity spotted on the cameras. It is set to open in the second quarter of 2018.
"We understand and appreciate that travelers are more concerned than ever about their safety and security and we have rigorous security procedures in place at all of our hotels in Mexico," Marriott said in an emailed response to questions. "Mexico continues to be a desirable destination for visitors from around the world and we've had very few cancellations for Holiday season due to this matter."
But the slowdown in Los Cabos since the travel warning is starting to show in other areas. International passenger arrivals dropped 2 per cent in September, the first decline in three years, and compares with a 20 per cent average gain for most of this year, according to airport operator Grupo Aeroportuario del Pacifico SAB and the Los Cabos Tourism Board. Other factors such as hurricanes and earthquakes in recent months contributed, said Rodrigo Esponda, managing director of the tourism board.
American Airlines Vacations, which packages trips to beach destinations in Mexico, said business had been rising about 25 per cent from a year earlier - until the travel warning torpedoed demand. Meanwhile, the online-booking site Best Day Travel Group has also seen a slowdown in reservations for the end of the year, said Director Julian Balbuena. Los Cabos is the hardest-hit destination with a 6 per cent drop, he said.
"We were having a good year for Mexico in particular," said Eduardo Marcos, president of American Airlines Vacations.
Gosselin, from the hotel association, said the travel warning went too far and may have been influenced by a shift in US policies toward Mexico following the election of President Donald Trump. There are also signs the alert's effect on tourism is waning, he said, as the peso is still trading about 26 per cent below its 10-year average. Marcos also said he thinks bookings will pick back up.
Even so, the hotel association is putting up 10 million pesos for a marketing campaign aimed at attracting more American tourists to Cancun hotels, Gosselin said. The move came after hotel occupancy growth fell from a clip of about 2 per cent last year to a drop of about 10 per cent, he said.
"Ninety percent of the economic activity here is tied to tourism," Esponda said in a phone interview from Los Cabos. "That's why security has to improve. We need tourism to continue improving people's quality of life - and it's a shared responsibility."