a new twist on an old scam

Over the last few years I've had a few phone scams tried on me. I've been warned several times taht i owe back taxes (I don't!)  The most notable was probably the "Hello, Grandma?" ploy. I received four calls within a week, using three differen't accents. This one was easy for me to hang up on. Actually they are all easy to hang up on. . Lately I don't even answer my phone unless I recognize the name of the caller. Recently, i've been hearing the warning to never answer 'yes' when some stranger asks you a question. OK, that's easy to avoid, but yesterday I heard a new twist on that one I think.  I saw that I had a message on my phone and when I listened to it, it was an obviously mechanical voice saying "Is this Lucinda? Please answer yes or no." That's all there was to the message. Obviously, since I was listening to voice mail I didn't answer anything. My first thought was that scammers are really getting lazy, not even making their own phone calls.  Then I realized that by doing it with an automatic calling system they can probably make many, many more calls than they could manually, upping their odds considerably of getting someone to say yes. I hate to sound negative but never say yes unless you want to end up being charged for something you never wanted to buy.