ANSWER: So they can't be searched for by any internet search engine!  See Below.

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http://minneapolis.backpage.com/FemaleEscorts/beautiful-one-of-a-kind-sexy-n-sweet-avaliable-now-22/11181410

JAMIE
Phone Number: 602*(642two182



http://minneapolis.backpage.com/FemaleEscorts/call-now-treat-yourself-20/11144939

RACHEL
Phone Number: 602/six4two/2one8two



http://mankato.backpage.com/FemaleEscorts/seductive-secret-19/11090739

AMANDA
Phone Number: 602*six42 *218two


-- Modified on 10/19/2013 6:33:58 AM

I search, with the actual numbers, and usually get "hits". Most hits are past ads which are often useful. When past ads with the same number show a different provider, I get concerned that the provider may be managed by a pimp or some other trafficking scheme. Granted that some providers share phones, it still raises a red flag of caution. Also, sometimes searches of phone numbers reveal other non-hobby related hits where that phone number has been used.