If this field were added to the advanced search page it would be a huge help for everyone IMO.  

The nearest big city for me is Las Vegas where I see most of my providers. I happen to be a huge fan of hairy pussy, and while there are there are a few ladies in Sin City who have the fuzz I loves there are only so many. Bald pussy obviously dominates in the adult playground. So if I had the option to check just 2 boxes in Advanced Search, Natural (or partially shaved) for pussy and cities visited (Las Vegas) I could see who might be coming out my way with a hairy cunt and book her. Good for me, good for her...........good for everyone, right?

I've been adding cities and states to my ads but short of putting it on my website or posting in the city forum it does seem it would be useful.

It used to be that reviewers could enter their city in the "Other Cities" box and that would enter the database on that Provider even if it didn't change her Profile. As such, if you search some parameters for a specific city you should get anyone with at least "Other Cities" entry with your city (LV).  
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I used to search my area and get such "weird" hits every now and then.  I'd check a Profile to see a home base in Chicago, Other Cities in LA and Orlando but find, maybe, one reviewer who saw her when she was touring in NY or Boston (but not visible on her Other Cities Profile list).  
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Now, a reviewer cannot edit or change pre-populated data fields.  It is weakening the database.