Here's why I would not want to be stranded on an island with a bunch of fashion models. To start with, I'm a guy, and I would be worked to death. I would give myself about two weeks, tops, and I'd be dead from exhaustion. Let me explain.
Professionally beautiful women must be relentlessly tended, pampered and nourished (albeit less than 1,000 calories a day). A desert island offers no such accommodations except for the lack of easy accessible sustenance. The "models" will not provide this set of services for themselves because it does not fall under their job description. These tasks would fall to the outsider. Wishing to please, establish order and perform as chivalrous knight errant would be the first step toward malnourished, overworked, sleepless death.
Compliments must continuously flow to foster slumping egos. This, mercifully, may lead to instant murder. To pay attention to one diva may well be interpreted as diminishing to another, inciting a potential woman riot. At this point, the lovelies may all rise up and kill the interloper with the shells they sharpened during the night. Oh, yeah, that's right... that would have been my job as well.