I have not seen it available for wireless, but I do know a feature like the one your requesting is available for landlines. I need to check my parents bill for the name as I do not have landline at home.
What it does it it tells the caller who is listed as unavail/blocked that the receipiant is not accepting unlisted calls. The caller then has to enter the number they are calling from (system knows if they lie and hangs up which we thought was funny).
CAM . . . you are so right that this is a very valuable feature and it should be offered and made free. Actually, the perfect place for it to be is WITHIN the existing usage controls . . . and may I note Verizon . . . (ahem) . . . we are ALREADY paying you for precisely this type of feature with that program. In fact, many members purchase that feature figuring and assuming that ability is already in there since it pretty much does everything BUT that!
We live in a dark world now were predators are attempting to contact our kids via every and any means necessary. It is the perfect camouflage for predators to call our homes under such anonymity. Verizon . . . if you are at all serious about providing protective tools such as all the rest that you provided in usage controls, why not provide what may well be the most important of them all? Or, as CAM so well phrased it . . . are you just looking to make money with no other interest at all on your radar screen?
Both Neko and CAM are right when they say that landlines have had this ability for a long time. I can use a third party program called "Trap Call" that can provide me with those concealed intrusive phone numbers within seconds! Why can't you do the same Verizon?