immunization nurses doing flu clinics

Hi. I have been doing adult public immunization clinics in my County for quite a few years. Currently we are conducting flu shot clinics. With the increase of patients with MCRE Advantage plans, our sign in staff often gets the wrong or incomplete insurance information. We are getting too many insurance denials because of inaccurate info. We would like to figure out a way to take a photograph or copy of the card(s) at the time of the registration. We tried taking a small copy machine along...too bulky. Someone suggested using a cell phone to take a picture of the card...is this a HIPAA problem? I understand there is a laptop that will take pictures. Has anyone ever tried that? Does anyone have a system that works?
I am so discouraged about the fact that there is no universal identifier of an Advantage plan card...it's hard to tell them apart from supplemental or pharmaceutical cards.