I can see something like this flying for a swinger resort like Hedonism II. Folks plan those kinds of vacations pretty carefully-and the costs of testing isn't that much compared to the rest of the vacation package.
I checked a vacation package for a Hedonism resort and for 5 days, it was $2500 for two people.
I find it very plausible that some folks might prefer such a vacation for $3100 and have some assurance that other guests at their destination were tested STD-(particularly when you consider there is already a pool of folk that are already testing regularly and would just have to have results faxed).
A lot of technical advances start out on the high end and then gradually filter down.
I'm not sure what the smaller high-end swingers resorts are like--but there sure seem to be a bunch of them around.