If you are selling an item on Craigs List or whatever you might use a google voice number so you dont have your real number out there for whoever to see.  (I get enough telemarketing calls as it is),  and once you sell the item or delete the ad, you are done with that phone number.  The phone company can give that number to someone else after its been inactive for two weeks.

the phone number isn't enough to let you know if the lady is real or fake,  you need more research but thought I'd let you know thats why some numbers bring up lots of other things.

As I'm blessed with(and cursed with)the insatiable curiosity gene,  whenever I read about a hobbyist who has been burned the first thing I do is Google the number of the "provider" in question.  Lo and behold, more often than not the number turns up neither reviews nor even "ads" on sites other than free sites.  My advise...except in very rare cases(or unless you're just in the mood to TOFTT), if a Google check doesn't make it clear that she's a legitimate companion be leery...forewarned is forearmed.  

That being said, there have been a couple of times when I've Googled  a fellow providers number out of curiosity and found both a sporadic history of ad's and things like babysitting services associated with the number.  I suspect that some younger and newer providers(or maybe just those with fewer resources in the beginning regardless of age)rely on just one phone for both the hobby and their personal lives.  That seems very odd to me, but maybe they just don't know any better.

Bottom line, Google is a very useful tool when trying to determine the legitimacy of a provider or a hobbyist.  It shouldn't be anyone's only resource, but it should definitely be among the first.