Technically, hispanic is not a race. Black and white are. Hispanic is about where they are from. Race is about skin color. I have met plenty of hispanics in my life that identify as either white or black depending on their skin color. If you think about it, there are Europeans from non English speaking countries who will say white but not speak good English. There are blacks in the same situation as well. But I get your concerns. I’m surprised the pictures didn’t tell you something.

That would be the same reason gals can say in their ads that they are 25 and weigh 120 pounds when in fact they are 38 and weigh 160 pounds.  
I am assuming you stayed for the session as you did not say you left, so her mission was accomplished of making money.  
When this happens you guys need to be walking out and then following up with the advertiser with the deceitful advertising. If you go through with the session (which she of course is assuming you will) this behavior is just being reinforced and will continue to happen.

With the editing of photos many times you cannot tell.

Thew following are identified:  

 
American Indian or Alaska Native. ...
Asian. ...
Black or African American. ...
Hispanic or Latino. ...
Native Hawaiian or Other Pacific Islander. ...
White.

I intentionally did not disclose whether I left or not.

I have been posting to S&P, General, and some other boards for many years about a BETTER way to make the Profile info more relevant and less ambiguous. There must be 100 or more such posts. Here are a few:
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http://www.theeroticreview.com/discussion-boards/ter-general-board-12/complexion-vs-cultural-heritage-vs-ethnicity-939340
"I have advocated that TER switch from a single "ethnicity" data field to two new fields: complexion and cultural heritage (or Country or Ancestry or something like that). ... And use a color chart for complexion.
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http://www.theeroticreview.com/discussion-boards/ter-general-board-12/complexion-hair-color-and-other-images-not-adjectives-972198
Complexion, Hair Color, and other IMAGES, not adjectives
http://www.theeroticreview.com/discussion-boards/suggestion-and-policy-4/silhouettes-complexion-chart-hair-color-chart-16055
Silhouettes; Complexion Chart; HAIR COLOR CHART
"I have suggested it over and over: get away from ambiguous adjectives and add COLOR AND IMAGE CHARTS to the review form and the Profile Viewing form.  
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1. Instead of thin, skinny, slender, could lose a few pounds, .... post a standardized set of silhouettes. A reviewer then picks the shape that matches his hostess the best, regardless of nomenclature. ..."
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http://www.theeroticreview.com/discussion-boards/suggestion-and-policy-4/images-not-adjectives-15844
Is Complexion too Complex for the Review Form?
"And the skin tone names explains why we hunger for these tasty morsels. "I'd like an Espresso Mocha Caramel with a swirl of Peach.""
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http://www.theeroticreview.com/discussion-boards/suggestion-and-policy-4/rgb-cmyk-pantone--use-a-color-chart-13492
http://www.theeroticreview.com/discussion-boards/suggestion-and-policy-4/i-have-several-10-out-of-10-suggestions-for-improving-reviews-16959
I have several 10-out-of-10 suggestions for improving Reviews.
"1. Switch to an X-out-of-Y scoring system for Performance.  
2. Replace the ridiculous "Ethnicity" data field with an UNAMBIGUOUS "pick one" data field:  
A. "Complexion" chosen from a color pallet (see the Mattell pallet, below), NOT some inconsistent color name that will vary from reviewer to reviewer.
B. Add another field for "Country of Origin" or "Cultural Heritage." I.e., one or two descriptors that will inform a reader if she is from a non-US country, talks with an accent, has non-US outlook on life, etc.. -OR- if she US born and raised even though her lineage is 100% from a non-US country. At that point, she may be "European" by heritage but, meeting her, she has all the attributes of any other US born and raised person. (This part of the suggestion needs more discussion.)
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People use "AA" for non-American black women to imply that the Provider has dark skin. Others use "AA" for anyone who IDs as AA even if they are as white as snow. I have met Brazilians who range from being as black as Espresso to as white as Coconut.  
3. Replace the ridiculous "Build" data field with a numbered chart of silhouettes or standard pictures (from the CLOTHING or fashion industry).  
4. I have had many other GREAT suggestions over the years to improve the system. In summary, the BEST suggestion is, "Put impposter in charge and give him an unlimited budget to implement his changes."

I think They Know

Exactly what they are doing and it is intentional deception.

You did quite alright!! I call that a win! But hey, that's just me.

I am a proud Latina American. My mother is white, and I have never identified as a white girl. I don’t speak Spanish. I know wtf I am and it’s a lot of different ethnicities. My mother is German & Yugoslavian. My Father is Mexican & Apache Indian. I would recommend sticking to independent & honest providers.

As to the question as to why they do it? Money.  

White escorts have historically been able to charge higher rates than minority escorts.

JohnDagger,
  Either the provider is half spanish & half white or the provider gets more business under the section that white providers place their ad.