apart from getting references, some providers want the active cell # to screen me.
no problemo - but i'm curious what & how they can learn.

Now I'm no expert, but I believe they want the cell number you'll be calling from simply as another measure of security.  They may likely call you at that number prior to your meeting and will then expect you to be calling the day of from the same number.  I know I'd be a little unnerved if the day of the appointment came and I got calls from an unknown number.

At least that's my understanding...

if you gave them a real cell number (personal versus hobby) they might be able to get your name or the account holders name.

I have this great little google+ tool that checks a lot of different venues for phone numbers...Granted if they give me a pre-paid phone this is no good. SO if they have no other references I ask for their PERSONAL cell phone number that I will never call, but just used to verify.  But if they don't like giving this to me then I want their real first name and last name. I can usually at least verify they are who they say they are this way as well. Although I see newbie clients I much rather prefer those who already have references and written reviews.

Thanks HHC.  Your input was very helpful.