I think jgeezy510 means the numbers of the girls themselves, instead of the PO. This makes sense if you really like the girl and want to follow her as she travels from org to org, or even for a visit off-hours. In my experience, most PO's don't keep track of where the girls go or are hesitant to send you to another org, so it's just best to talk to the girl directly.
I like jgeezy510's idea. The only issue I'd have is POs that text you from random numbers asking you to visit. Also, if saving the numbers in contacts instead of maintaining them in the blocked list, it's possible your contacts might leak in a way you don't know.