Apparently it's no longer safe to say the word "yes" on the telephone.

What kind of #*@!# world are we creating for ourselves?

It’s not a Verizon commercial: If you receive a phone call from someone asking “can you hear me,” hang up. You’re a potential victim in the latest scam circulating around the U.S.
Virginia police are now warning about the scheme, which also sparked warnings by Pennsylvania authorities late last year. The “can you hear me” con is actually a variation on earlier scams aimed at getting the victim to say the word “yes” in a phone conversation. That affirmative response is recorded by the fraudster and used to authorize unwanted charges on a phone or utility bill or on a purloined credit card...
But how can you get charged if you don’t provide a payment method? The con artist already has your phone number, and many phone providers pass through third-party charges.
In addition, the criminal may have already collected some of your personal information -- a credit card number or cable bill, perhaps -- as the result of a data breach. When the victim disputes the charge, the crook can then counter that he or she has your assent on a recorded line.  

More details on what to do if you've been victimized and how to dispute the claims at CBS News.
I believe I received one of these calls this past week.  The caller (to my private cell which is not a publicly known number) started by saying he was calling in response to my job application.  I denied such and he replied "Can you hear me ok?"  My response was "you've either got the wrong number or you are spamming me" and I disconnected.
Scum.