My opinion on Grid Girls, and it's not about about an attractive woman not being able to find work elsewhere or how difficult the job is or isn't, so if you think that, you are missing the point. It's about freedom of choice.
To me it's PC gone wrong. Quit taking away women's right to choose their profession. They'd never ban men from the ability to choose to be drivers, mechanics, or PR reps for the sport they love. These women are educated on the products they promote and are never forced to do anything they are not comfortable with, including which outfits they decide to wear. It's just another example of a small group of people who "think they know what is best for women" deciding what women can and cannot do without having any knowledge of the actual job. How about letting women decide what they want to do for a living and checking your facts before deciding something is sexist or demeaning.
Here is an article from a grid girl that sums it up nicely.