Ask for documented proof, i.e. The certificate itself! That way you can see when it is valid until or to and from....
I would only save this for 2nd/3rd round interview though. Cheers Dr James McGee, MCSE, CCNA, CCDA, CCNP, CCDP, CCIE, CCSE, CCSA, CISSP, BSc, MSc, PHd,
