I've heard of this as a strategy in the telemarketing world to "slam" people. When they ask "can you hear me ok" and you say "yes", they now have a recording of your voice saying "yes". Now they just doctor their tape to put their sales pitch in front of your "yes". The piece I don't know how they accomplish is actually charging you for something without getting credit card numbers, etc.
Called am left no message. I am so sick of all of these calls I keep getting from so many numbers. Hello I am not answering a number I do not recognize. Obviously it is not that important or they would leave a message