Some people I interviewed while in D.C. would just tell me they were working and didn't want their present employer to know they were changing jobs in case they didn't get this one. I would call their present job and say I was verifying the info given me for credit, such as time on the job and then I'd ask is their longevity with this company a good bet...This way you know if they work there and they are valued. This way I got what I needed without risking their present position.