It's usually a scam - not (only) against Fairfax residents, but against the workers. By sending the (usually) kids hundreds (sometimes) of miles away from where they live, the kids MUST produce. If they do NOT, they are fired - and, of course, can't get back home.
So they produce no matter how many hours it takes.
In addition, the folks who drive them here put them up in cheap motels and typically charge them for the motel as well as their food.
BTW, the people who are victims of this come in all flavors - a week or three ago some young highly-tattooed (*) chick came around selling windows or subscriptions or something - she was walking with a cane with her foot/ankle wrapped up. I commented that it wasn't exactly the right time to be walking around selling and she replied "I don't have a choice"...
This scam against the sales folks has been written about many times - a quickie google using the right search terms turns up article after article describing the horrendous ROI the kids get - they're MUCH better off at McDonalds.
It happens multiple times per year so the guys making the bucks obviously aren't going to stop anytime soon.
http://www.nytimes.com/2007/02/21/us/21magcrew.html?fta=y&_r=0
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(*) Tattoos are NOT cheap - it's sadly amazing to me that someone struggling to live is spending whatever she makes on VERY expensive tattoos isntead of, you know, the future. Tattoos can come later.