Police say a phone-based scam in the United States has seen fraudsters attempt to gather people's voice prints, presumably to attack biometric security systems, but there are doubts that such a system would actually work.According to authorities, the attackers will often use the phrase “Can you hear me?”This has led to speculation that if victims say “yes”, that a recorded voice print can then be used authorise fraudulent charges to that person's phone, utility or credit card bill.Susan Grant, director of consumer protection for the Consumer Federation of America, told CBS: “You say 'yes,' it gets recorded and they say that you have agreed to something.”She urged the public to simply put the phone down to unsolicited callers who pose that question: “I know that people think it's impolite to hang up, but it's a good strategy.”However, the myth-debunking website Snopes has raised doubts about the reports, saying: “The 'Can you hear me?' scam for now seems to be more a suggestion of a hypothetical crime scheme than a real one that is actually robbing victims of money.”The site's investigators found “no indication that anyone who had actually been scammed out of money by saying 'yes' to a caller had stepped forward”.Typically voiceprint based security systems will ask a user for a passphrase, and few are likely to use the word “yes”.