We too have blocked private /unknown numbers, with the effect of receiving some pretty strange cid names.  I actually called "Stanky Mark" about midnight their time (3:00AM ours).  He was quite perturbed.  He kept asking my name, which I made up and repeated over and over.  I said "You called me.  Why did you call me.  I am calling you back."  He asked if I knew what time it was.  I said "no".  He seemed annoyed to be called at midnight, his time.  I just hope this is not some poor sucker who had his number stolen, but his voice sounded very familiar from a message left regarding water cut off for our city if we did not pay $112,000.  I did call that person back frantic, asking why our water was turned off (it wasn't), the same night as I called Stanky.  Insomnia, boredom and page upon page of junk calls drive one to the brink of insanity.  By the way, I blocked my number for these calls.  Stanky seemed pissed that the cid said "unknown".  Imagine that???

Recently found out how to block "private /unknown" numbers on phone system.  Since then you would not believe the various fake names that have been dialing the blocked number.  The above number called w/ the caller ID "Stanky Mark".  Needless to say the call went unanswered and no message was left.  Also, most unwanted calls had been coming from Arizona area codes.  Since blocking unknown #s, we have received an inordinate number of calls from our local area code.   Hmmm...Spoofing???