I believe that with more data the new variant is between 50 and 60% more transmissible. Still more than enough for it to cause a major spike in new cases which will result (about two weeks later ) in a major spike in hospital admissions. And an increase in the number of people unwell for several weeks (long Covid19 ) .
In every country the strategy has been to keep the number of hospital admissions down to a level with which their health system can cope and the latest variant threatens that.
I hope that the Mexican authorities quarantine all these pax in their hotel rooms. With those numbers it is almost certain that a few will have been incubating the disease when they left and if they are allowed to mingle the whole resort could become infected.