A few of the providers I've reviewed have white-listed me without my asking. Should I be flattered or is this just a smart way to make a  client want to come back?

It seems that they thought enough of you and enjoyed your company, so yes maybe you should be flattered but keep in mind, it is a business for them.  Yes, they probably are using this as a means to lure you back to see them again.

Likewise if she recommends you on Date-Check, etc. Everything goes both ways, so I'm also more likely to recommend her to fellow hobbyists not just because of her GFE skills but also her attitude/thoughtfulness toward me.

I don't, but many do. If I WL a guy, it is my Golden stamp of approval, meaning he did so much more than not rip me off, and was clean. You might write a review for these ladies, but don't feel pressured to lie because they gave you a WL. I've white listed guys who only gave me 7s.

Can someone tell me how do I whitelist someone?  
xoxo Bridget

Hi Bridget,