Yes, I had that in mind. The phone poll will be changed regularly as a protective measure. I have PITA when I'm dealing with craiglist, it works for me right now but I want to share that service(pro version) with other people.
The problem with any service like this is that you'll inevitably get a bunch of calls meant for previous users of that number. And from an article I read a while back they tend to be johns trying to get a hold of prostitutes.