Most companies know that references are completely useless anyway because people game the system and only provide references that will speak very highly of them. Sometimes they even go as far to have their friends and family pose as fake references. Do you wanna sit around checking these references and listening to how great this candidate is from their friends and family members all day? Completely senseless waste of time.
Also, many larger companies with legal departments only allow the verification of facts like dates of employment, pay rate, job duties, etc. They don't want to give their personal opinion of a former employee because if they did they could end up in legal trouble when that person sues them, pays off the judge and wins.
The job market is a fiercely competitive environment and people gotta be ruthless if they really want that job. It really takes a certain kind of person. Almost a criminal kind of person. You gotta be willing to do whatever it takes when your livelihood is on the line although most people won't admit it.
So, as a hiring manager, you gotta figure out a way to overcome that. If I were you I'd secretly check Yahoo Answers for their responses or install spyware on their computers or something.