I've heard that too, but I'd like to actually see the study of it. From anedotal experience, if you bring a woman to a strip club with female strippers, the strippers will hang around longer...
But as to making a man more attractive because he has a "wing-girl" hanging on him, I'd really like to see a serious study done on that.
I have heard (not read the evidence), that simply giving a reason for a favor increases the chances of people granting favors over just simply asking. So perhaps, just adding
anything to the "can you do me a favor" question would cause an increase.
I still of the opinion that this whole thing is nothing more than simple psychological tricks that you can learn by studying stage magic. There are ways to momentarily distract the "critical thinking" of a person. Note the word I used: "distract". It's nothing more than that. Any "sustaining of distraction from critical thinking" is up to the desire of the recipient.
What these people are doing is taking basic, simple techinques and blowing them up into a miracle. Just doesn't work that way.